Antony Law

Matric No: S1125113

Honours Research and Project Methods (MHG405279)

Module Leader: Brian Shields

Final Honours Project Report

A Comparison Study of Simple to Complex Passwords Implementation in WLANs Security Framework

Project Supervisor: Dr. Ali Shahrabi

Second Marker: Iain Lambie

Submitted for the Degree of BEng (Hons) Network Systems Engineering 2015-2016

“Except where explicitly stated all work in this document is my own”

Signed: Date:

AbstractThe 802.11 standard allows for wireless communication by transmitting data through the air. This offers great flexibility and ease of installations as compared to wired networks. However, propagated radio signals are not confined, allowing interception of data to be easily achieved. This leads to an unsecure data transmission. Thus, Wired Equivalent Privacy (WEP) protocol was initially developed to achieve data confidentiality, integrity and authorisation. Later, flaws were discovered, which lead to the creation of Wi-Fi Protected Access (WPA), and finally, 802.11i protocol, to provide secure wireless communication. WPA and 802.11i is “password” protected, and is used to authenticate a client. Furthermore this makes WPA and 802.11i vulnerable against a “brute-force” or a “dictionary” attack, and the attack is only successful if a client is associated with the AP or router of the target network.

The aim of this project is to evaluate the impact between “simple” and “complex” passwords implemented into WPA and 802.11i, to determine which is most resistant to cryptanalyze. This experimental project will be conducted in a lab environment to ascertain this information, and either a brute-force or dictionary attack will be launched through the oclHashcat program against the simple to complex passwords. Password scenarios created must meet the factors ease of use and memorability to simulate as closely as possible to real-life scenario, and two dissimilar password strength meters (My1login and The Password Strength Meter) is also used to validate the password scenarios into simple or complex category. The metrics of interest are success and failure of the attack, along with the recorded time of success only, to establish the variance in security level provided by simple and complex passwords. In addition, “Aircrack-ng” program supplied by Kali Linux OS will be used to capture the four-way handshake packets to distinguish any differences, if any, between both protocols (WPA and 802.11i).

In previous studies, it is identified that increasing the password length to be more secure, than creating meaningless password with a mixture of characters. Increasing password length achieves memorability and usability without decreasing security. Complex passwords are more secure than simple passwords, but the success of password cracking is subjective, due to the hacker’s intelligence and wordlist applied. The outcome of this experiment emphasises the importance of user awareness in selecting passwords and protocols. Most importantly, I.T specialists and general users can benefit in creating an educated password to provide a satisfactory level of security under their control.

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AcknowledgmentsI would like to thank my family and friends for the consistent support throughout the development of my Honours project report. In addition, I appreciate the time my supervisor offered me to regularly monitor my work and kept me in the correct direction.

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Acronym

Wi-Fi – Wireless Fidelity

WEP – Wired Equivalent Protocol

WPA – WiFi Protected Access

OS – Operating System

IEEE – Institute of Electronics and Electrical Engineers

WLAN – Wireless Local Area Network

ICV – Integrity Check Value

IV – Initialisation Vector

RC4 – Rivest Cipher 4

WAP – Wireless Access Point

XOR – Exclusive OR

TKIP – Temporal Key Integrity Protocol

PSK – Pre-Shared Key

MIC – Message Integrity Check

RSN – Robust Secure Network

EAP – Extensible Authentication Protocol

AES – Advanced Encryption Protocol

RADIUS – Remote Authentication Dial-In User

IPv4 – Internet Protocol Version 4

CPU – Central Processing Unit

GPU – Graphics Processing Unit

PMK – Pairwise Master Key

HMAC – Hash Media Access Control

SHA – Secure Hashing Algorithm

LEAP – Lightweight Extensible Authentication Protocol

TTLS –Tunnel Transport Layer Security

PEAP – Protected Extensible Authentication Protocol

FAST – Flexible Authentication Secure

MD5 – Message-Digest 5

OTP – One-time Password

NIST – National Institute of Standards and Technology

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SSID – Service Set Identifier

WNIC – Wireless Network Interface Card

ISO – International Organisation for Standardisation

CD-ROM – Compact Disc Read-Only Memory

CLI – Command Line Interface

GUI – Graphical User Interface

Table of Content

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s

Chapter 1...................................................................................................................................1Introduction..............................................................................................................................1

1.1 Project Background..........................................................................................................11.2 Project Outline & Research Question..............................................................................3

1.2.1 Project Method..........................................................................................................41.2.2 Research Question.....................................................................................................41.2.3 Objectives..................................................................................................................41.2.4 Hypotheses................................................................................................................6

1.3 Report Structure...............................................................................................................71.3.1 Literature Review......................................................................................................71.3.2 Methodology.............................................................................................................71.3.3 Results.......................................................................................................................71.3.4 Final Discussion & Conclusions...............................................................................8

Chapter 2...................................................................................................................................92. Literature Review.................................................................................................................9

2.1 Wireless Local Area Networks (WLANs).......................................................................92.2 Wireless Security Human Factors and Technical Factors..............................................102.3 WEP Weaknesses...........................................................................................................112.4 WPA and WPA2 (802.11i) Encryption Technique.........................................................11

2.4.1 802.11i Authentication (EAP).................................................................................122.5 Capturing Four-way Handshake....................................................................................12

2.5.1 Security Level Rollback Attack..............................................................................133 Passwords.............................................................................................................................14

3.1 User Password Creation.................................................................................................143.1.1 Potential Password Combinations (Simple to Complex Passwords)......................153.1.2 Mnemonic Password VS Regular Passwords.........................................................15

3.2. Password Meters...........................................................................................................163.2.1 Measurement of Password Strength........................................................................16

3.3 Alternative Password Cracking Methods.......................................................................17Chapter 4.................................................................................................................................194. Methodology.......................................................................................................................19

4.1Primary Research Method...............................................................................................194.2 Intended Experiment......................................................................................................20

4.2.1 Construction and Configuration of Topology.........................................................204.2.2 Implementation.......................................................................................................23

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4.2.3 Password Scenarios (Test Data)..................................................................................264.2.4 Password Cracking Approach.................................................................................28

5. Results.................................................................................................................................335.1 Four-Way Handshake (Data) Packets............................................................................33

5.1.1 Comparison between WPA and WPA2 Data Captured............................................345.1.2 Simple Password Scenarios VS Complex Password Scenarios Implemented in WPA and WPA2...............................................................................................................35

5.2 Variance of Security Due to Simple and Complex Password Scenarios.......................385.2.1 Comparison between Simple and Complex Passwords Implemented in WPA and WPA2...............................................................................................................................385.2.2 Comparison between WPA and WPA2 protocols against Simple to Complex Passwords.........................................................................................................................40

Chapter 6.................................................................................................................................426. Final Discussion and Conclusions.....................................................................................42

6.1 Summary of Project........................................................................................................426.2 Discussion of Results.....................................................................................................43

6.2.1 Research Question Findings & Hypotheses............................................................436.2.2 Limitations and Further Works...............................................................................456.2.3 Advantages..............................................................................................................46

6.4 Conclusions Remark......................................................................................................46References...............................................................................................................................48Additional Bibliography........................................................................................................53

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List of Figures

Figure2.1 Hashing Process…………………………………………………………………...12

Figure 2.2 Deauthentication Attack…………………..............................................................13

Figure 4.1 Experimental Topology..........................................................................................21

Figure 4.3 Launching Dictionary-Based Attack…………………………………...................29

Figure 4.4 Local Telephone Mask and Brute-Force Attack Configurations…………………30

Figure 4.5 Possible Permutation Based on Typical Passphrase “Password”…………..…….31

Figure 4.6 Rule-Based Attack…………..……………………………………………………32

Figure 4.7 Rule-Based Total Time Estimated to be Run………………………………….....32

Figure 5.1 Data Packets Captured in WPA and WPA2 with Simple Password Scenarios Implemented………………………………………………………………………………….34

Figure 5.2 Data Packets Captured in WPA and WPA2 with Complex Password Scenarios Implemented………………………………………………………………………………….34

Figure 5.3 Data Packets Captured in WPA-PSK against Simple and Complex Password Scenarios Implemented………………………………………………………………………35

Figure 5.4 Data Packets Captured in WPA2-PSK against Simple and Complex Password Scenarios Implemented………………………………………………………………………36

Figure 5.5 Comparison between Tsitroulis, (2014) summarised results with WPA2-PSK Complex Password Scenarios of Averaged Data Packets Captured…………………………37

Figure 5.6 Success and Failure Rate of Simple and Complex Password Scenarios Implemented in WPA-PSK + TKIP………………………………………………………….38

Figure 5.7 Success and Failure Rate of Simple and Complex Password Scenarios Implemented in WPA2-PSK + AES…………………………………………………………39

Figure 5.8 Comparison between WPA and WPA2 with Simple Password Scenarios Implemented…………………………………………………………………………………40

Figure 5.9 Comparison between WPA and WPA2 with Complex Password Scenarios Implemented…………………………………………………………………………………41

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List of Tables

Table 4.1 Assigned IPv4 Addresses………………………………………………………….22

Table 4.2 Test Data: Simple and Complex Passwords……………………………………….27

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Chapter 1

Introduction

This section will provide an overview of the research area about wireless networks which has become ubiquitous due to their advantages. However, security aspects were commonly ignored due to its convenience, which became a drawback. This motivated the development of wireless encryption protocols to provide wireless security, and how human factors influence the level of security of a wireless network. Therefore, human factors were a fundamental aspect to consider.

1.1 Project Background

In 1997, the Institute of Electronics and Electrical Engineers (IEEE) had devised an 802.11 standard that achieved wireless network communication in a Local Area Network (LAN) known as a Wireless LAN (WLAN), without the need of wired connections between devices. Kumar et al., (2012) indicated that WLAN communication operates on an unlicensed frequency band of 2.4 GHz, 3.6GHz and 5GHz. Similarly, Li and Garuba, (2008) stated the advantages offered (but not limited to), mobility and ease of installation. Thus, a recent study had illustrated the exponential growth of WLAN markets for both consumers and enterprises due to the advanced wireless standard 802.11ac, offering enhanced performance (Worldwide WLAN Market Shows Continued Growth in Second Quarter of 2014, according to IDC (International Data Corporation, 2014). Furthermore, this encouraged the increase of unique Wi-Fi networks that existed from 1st of Feb. 2014 to 3rd of Feb. 2015 by 41.8% (https://wigle.net/stats, 2010). This implied the demand for WLAN technology is substantial and a study conducted by Zhang et al., (2012), identified that WLAN technology is necessary in day-to-day activities of work. On the other hand, Bulbul et al., (2008) emphasised the security concerns that radio transmission can be intercepted by a hacker. Thus, the WEP protocol was introduced in order to provide a level of security equivalent to wired networks. Borisov et al., (2001) suggested this protocol will closely match the security of a wired network, with the aim to provide confidentiality of data and integrity of data against hackers.

The working of WEP was discussed by Kumkar et al., (2012) to demonstrate how these goals are met. Firstly, the plaintext required to be transmitted is appended with the Integrity Check Value (ICV), in order to ensure data is not altered. Secondly, a key stream cipher is required for data encryption. This key stream is a combination of a 40-bit WEP key and a 24-bit Initialization Vector (IV) together, that is implemented in the RC4 (Rivest Cipher 4) algorithm, producing a 64-bit key length. Yin and Cui, (2011) defined the WEP key as a password that is used to authenticate a user on an Access Point (AP), also with an extended 104-bit key length. This also implied that passphrase length is limited to the key length size. Lastly, the exclusive OR (XOR) Boolean operator is used to generate the ciphertext along with an IV.

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While WEP’s objective was to ensure secure wireless data transmission, many flaws were discovered, which resulted in the failure to achieve its objectives (Borisov et al., 2001). The improper use of RC4 algorithm, small sized IVs and inappropriate use of the root key, makes it easier for a hacker to exploit WEP. Previously mentioned above, the key stream cipher is generated with the WEP key and IV. Therefore, sufficient amount of IVs captured, will cause the plaintext to be obtained by a hacker because the same ‘root’ key is also used. The extended size of IV also did not provide sufficient security, demonstrated by Walker, (2000), because the RC4 architecture was poorly designed. Fluher et al., (2001) further demonstrated that the key recovery attack on the RC4 key scheduling algorithm was successful, as the first 3-bytes of the IV is always sent unencrypted, allowing the weak keys to be identified in order to crack the key. A study by Yin and (Cui, 2011) commented on the RC4 algorithm being ineffective due to its simple keys. This implied that simple passwords are used, causing the exploitation for a cryptanalysis easier. Although complex passwords benefit from being more resistant to cracking, Yin and Cui, (2011) further expanded that it does not provide satisfactory security for users, due to its flawed architecture, referring above the leaked IV and same root key being used, allowing the plain text to be recovered.

A recent study, (Mavridis et al., 2011), found that organisational confidence in deploying wireless networks was influenced by WEP’s insecurity. However, the Wi-Fi Alliance had introduced an interim solution to address flaws identified in WEP (Everts and Editor, 2003). This protocol, namely Wi-Fi Protected Access (WPA) was ratified in 2003, with new and improved mechanisms. Li and Garuba, (2008) demonstrated how the new mechanism TKIP –Temporal Key Integrity Protocol, is used to improve the encryption of data, which hashes the Pre-Shared Key (PSK) with an IV, along with a Message Integrity Check Protocol (MIC or Michael), to avoid tampering of data. Moreover, the 128-bit key and 48-bit IV are used as a counter to avoid the replay attack that is implemented into the RC4 algorithm, which produces a sequential key, and together with the transmission of data, will be implemented into the XOR cipher to generate a ciphertext. Bhagyavati et al., (2004) stated that WPA is cost-effective and convenient due to its compatibility with existing WEP devices, also only requiring a firmware update. In contrast, Bhagyavati et al., (2004) also identified a drawback of WPA due to the use of simple passwords, chosen by users. In addition, Moskowitz, (2003) further supported that dictionary or brute-force attacks can be launched offline. Consequently, hackers are able to obtain the password files and decrypt the passwords on their demand with no limits of attempts and time, as password files are obtained. However, if it was an “online” attack then hackers may be limited to a number of attempts, if password “lock-outs” have been implemented as a security measure (Han, Wong & Chao, 2014).

Altunbasak et al., (2004) had introduced the IEEE 802.11i (WPA2) with a discussion of the mechanisms in place. The 802.11i comprised of upgraded architecture – Robust Secure Network (RSN) - utilising 802.1x, Extensible Authentication Protocol (EAP), and Advanced Encryption Standard (AES), as a secure authentication and key management technique, performing the “four-way handshake” (Yin and Cui, 2011). Shao et al., (2010) and Mavridis et al., (2011) clarified the need for necessary upgrades of existing old WEP equipment because the demand on computational resources are intensive.

Kumar et al., (2012) defined the two available modes of WPA and WPA2, which are; PSK and Enterprise. Firstly, the PSK is suitable for personal use or small organisation (SOHO – Small Office Home Office), which a user is granted access with the valid key (passphrase), compared with the Access Point (AP) stored keys. Secondly, Maple et al., (2006) also described in detail how Enterprise mode is used. EAP is typically utilised by large enterprises

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with the requirement of a remote server, typically Remote Authentication Dial-In User (RADIUS), to store the credentials of each user belonging to that enterprise, and 802.1x protocol will relay user’s credentials between the AP and remote server, for (Client-to-Server) authentication. If the user’s entries (credentials) match, then access is granted. This suggested that complex password could lead to a more secure network as it is assumed to be more difficult to brute-force.

With the security protocols continuously improving, Chen and Chang, (2015) defined that WPA and WPA2 are considered to provide sufficient levels of security, with regards to design architecture perspective. Bhagyavati et al., (2004) stated that technical factors are important as much as human factors. Tsitroulis et al., (2014), also further supported this statement and commented that both protocols are susceptible to traditional brute-force and dictionary attacks, as users are likely to choose weak passwords due to convenience, something that is simple and memorable. A previous study conducted by Shay et al., (2010) supported that common passwords used are typically made up of dictionary words and names. In addition, it was further expanded that students felt that using complex passwords are inconvenient but proved to be more secure, which implied that complex passwords are usable. This highlighted the importance of using complex passwords, increasing the resistance of security against a successful brute-force and dictionary attack. Later, Tsitroulis et al., (2014) emphasised that dictionary or brute-force attacks are only successful if the password is available in the wordlist.

Krekan et al., (2012) noted that for a broad wordlist to be generated, a high demand of computational resources will be required. However, recent studies from Florencio and Herley, (2007) and Duggan et al., (2012) demonstrated, it is inefficient and unrealistic to test “meaningless” password candidates, taking into account the key length of 8 – 63 characters and total password combinations from 958 ~ 9563. Moreover, the required memory consumption to store the generated wordlist is infeasible. Therefore, Krekan et al., (2013) and Chen and Chang, (2015) introduced a logical and statistical approach that are performed with the available software, such as “oclHashcat” and hardware resources such as the General Purpose Graphical Processing Unit (GPGPU), with enhanced performance compared with a high-end CPU.

From a recent study conducted by (Krekan et al., 2012), it stated that approximately 77% of I.T administrators do not have a computer security background. This implied that more often than not, users are not aware of security risks. Therefore, it would be informative to conduct an experiment, emphasising the influential effect between simple and complex users’ passwords that are implemented in a security protocol, in order to determine which is most resistant to cryptanalysis.

1.2 Project Outline & Research Question

This section will define the research question to be answered, with justification of the motivation of this study. This project will include a discussion about the project type and project aims to be achieved, with the associated hypotheses.

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1.2.1 Project Method

This project type is experimental.

Initial research within the field of wireless security encryption protocol has identified extensive studies based on WEP encryption protocol, revealing the existing vulnerabilities (Sheldon et al., 2012). This had driven the author to further research on the two available encryption protocols, WPA and WPA2. Both protocols have been proved to be susceptible against brute-force and dictionary attacks, because of the security gaps caused by users implementing weak, easy-to-guess passwords (Lashkari et al., 2009). A recent study conducted by (Chen and Chang, 2015), indicated the uniqueness of their project as empirical data (encrypted password files) utilised are real-life passwords obtained in a public area of Taiwan. It is impractical for the author to obtain real-life passwords within GCU campus. This had encouraged the author to create realistic passwords as test data, which simulate as closely as possible to reflect on human behaviour taking into account the memorability and usability factors as (Duggan et al., 2012 and Shay et al., 2010) emphasised both factors strongly influence a users’ choice of password selection. Therefore, this project will emphasise for all users of wireless networks, that human factor is a fundamental aspect to achieve the WPA and WPA2 full security potential. Through the extensive research carried out, it suggests the author to conduct the study in a physical lab environment as no previous research papers have performed the experiment in a simulated environment. Simulation experiments with regards to wireless security encryption protocol was identified to cause significant problems and misleading results, this implied that undertaking this project through the use of simulation modelling would be unrealistic and inaccurate (Heidemann et al., 2000).

1.2.2 Research Question

“How does the level of resistance vary according to simple and complex passwords utilised against a brute-force or dictionary attack on a system, when implemented into the wireless security protocols WPA and WPA2 (802.11i)?”

1.2.3 Objectives

The aim of this project is to determine the level of resistance between a ‘simple’ and a ‘complex’ password implemented in a wireless access point (WAP) with two wireless security encryption protocols enabled in turn, WPA-PSK and WPA2-PSK. The metrics which will be captured are the success and failure of the attack, along with the total time of success only, as a result for analysis to conclude the strength of the security provided, along with highlighting their effectiveness and emphasising the effort required for an adversary to recover each password. In addition, the results will be used for comparative analysis to find out the effects (if any) between the two wireless encryption protocols, WPA-PSK and WPA2-PSK. In order to conduct this project, a list of primary and secondary objectives have been identified and investigated.

The Objectives to be answered through an extensive literature review;

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Investigate how human factors are considered as a security gap in protecting their wireless network.

This will involve extensive research based on the human factors which cause security gaps in the network, and to identify the main issues fuelling these insecurities caused by the user, and how this project will attempt to improve the human behaviour commensurate to the security level.

Identify the appropriate simple to complex passwords as test data for realistic results.

Research based on users’ password creation will help the author identify the most suitable password-composition policies to simulate a real-life user password creation, and help distinguish passwords into the appropriate category from either “simple” or “complex.”

Investigate the logical approach of using a brute-force or dictionary attack through previous literature and identify the most efficient and suitable method for this project.

Previous studies contained within the literature review (Tsitroulis et al., 2014), stated that “intruders are only successful in password cracking if the given password is available within the wordlist”. From these previous studies, it is clear to see that the researchers have adopted their own logical approach to password cracking experimentation. This should also be applicable for this project, and from the understanding and knowledge gained from the literature review, devising a logical method for this project should become attainable.

It is essential to outline the list of objectives that will be performed in order to complete the project successfully.

Lists of primary objectives are identified below;

Construction and Configuration of the topology to mimic the real-life scenario of a valid client connecting to a wireless access point.

o This will include assigning IPv4 (Internet Protocol Version 4) addresses to WAP and the PCs, prior to connecting the PCs to the WAP.

o Installation of penetration tool, Kali Linux on the bare-metal of another dedicated physical machine.

Implementation of the required test data.o Test data includes simple and complex passwords. o Perform brute-force or dictionary attack against the test data, by using a PC

with a “high-speed” GPU processor installed. In this case GEForce GTX 660ti (GPU) was purchased.

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Evaluate the metrics from the launched attack. o Record all the required metrics.

Total time of success. Success or failure of the attack.

o Determine the level of resistance provided by simple and complex passwords.

1.2.4 Hypotheses

H1: Complex passwords will be more resistant against a brute-force or a dictionary-based attack, than compared with a simple password implemented in WPA and WPA2 encryption protocol.

Through the literature review the author is able to distinguish between a simple and complex password in Section 3.2. Komanduri et al., (2011) indicated that complex passwords are to be more resistant against password cracking than with simple passwords, such as increasing the length of characters as the number of combinations raises exponentially. Therefore, simple and complex passwords will be tested against brute-force or dictionary attack and the metrics total success time and success or failure of the attack can disprove or prove the hypothesis H1.

H2: Complex passwords are assumed to be more resistant against password cracking, than compared with simple passwords. Therefore, more four-way handshake (data) packets are expected to be gathered from a complex password scenario than compared with a simple password scenario.

The experiment undertaken by Yin and Cui, (2011) demonstrated that while capturing the IVs to crack WEP encryption protocol, the results discovered that complex passwords gathered a higher amount of IVs than compared with simple passwords used for WEP. Furthermore, Tsitroulis, (2014) undertook an experiment attacking WPA2 protocol also recording the amount of data packets captured for all password scenarios. However, the most complex password did not require the most packets to be captured, thus, assumed unpredictable. For example, password “Icecream” captured ‘22794’ packets and another password scenario “Sky$kr@p3r!newy0rkc1ty%” captured ‘14761’ packets, which could not be declared that complex passwords require more data packets to be captured. Therefore, it would be of interest to prove or disprove this statement when utilising both protocols, WPA and WPA2, and the metric recorded was “data packets captured” for validation.

H3: WPA+TKIP and WPA2+AES will be cracked utilising the same method. Thus, it will have no or negligible difference between both protocols, when cracking the password scenarios, simple to complex.

WPA and WPA2 encryption protocols consist of two different encryption standards, which are TKIP and AES respectively. AES encryption demands for an intensive processing power than compared with TKIP encryption technique, consequently we are lead to believe that

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deciphering the hashed password file would be more difficult against AES than TKIP. However, it was proven by Yin and Cui, (2011) that encryption bit size does not impact the deciphering process of WEP. Therefore, it can be predicted that AES and TKIP will have no effect when deciphering the captured four-way handshake because encryption bit size did not influence the cracking of WEP. The metrics recorded to validate this statement will be the success rate (%) and the total success time required to crack only. The total time taken for a failed attempt will not be recorded as this will have no significant value to justify hypothesis H2, further discussed later within the report (Section 4).

1.3 Report Structure

1.3.1 Literature Review

In Section 2 & 3 of the report it will focus on the Literature Review, which will be used to provide a better level of understanding and knowledge of the project topic area. The Literature Review will then be used to “drive” the project forward and subsequently put the author in a position to perform the project experiment, from which an answer to the research question should be provided.

1.3.2 Methodology

Section 4 will provide insight as to how the project experiment will be conducted in order to fulfil the primary objectives listed in Section 1.2.3, which will include the following details:

Experiment topology. Device information and configurations. Software used within the experiment, (such as penetration tool). Simple and complex password scenarios (test data). Commands used and the attack launched.

The methodological approach chosen will also be justified why it is most appropriate for this experiment.

1.3.3 Results

In order to interpret the results clearly for the reader, all findings from the conducted experiment were presented in Section 5. The metrics were further justified with the appropriate literature to outline the significance, in relation to the project. All results were then summarised and displayed appropriately with detailed commentary, to discuss the definition of each result, with regards to the research question stated in Section 1.2.2. In addition, to also test the hypotheses mentioned in Section 1.2.4.

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1.3.4 Final Discussion & Conclusions

Further discussions based on the results, and status of the hypotheses is included in Section 6. The final conclusions of our work were consistently contrasted with the relevant work of others to highlight any notable differences. Dissimilar findings were also identified with the appropriate justification. Therefore, limitations of our work were detailed along with the further work available to improve on the results obtained and drive the project experiment further. Finally, a conclusion of the overall project will be concluded reporting the value of the study.

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Chapter 2

2. Literature Review

The literature is considered as an essential element with regards to the overall project, as this provides the author a basis of knowledge about the chosen project area. The author will undertake in-depth research of the project area to gain a deeper understanding of the related field of work and the methodologies utilised by previous researchers. This allows the author to conclude upon the most appropriate methodologies to utilise for their project and how the project will be delivered, and in turn, be of unique value within the research area.

2.1 Wireless Local Area Networks (WLANs)

The first “wireless fidelity” (Wi-Fi) standard was released in 1999, by IEEE Working Group (WG), this standard was 802.11a with the capability of transferring data up to 2Mb/s (Megabits per second. In addition, Choi et al., (2014) conducted a study of the Wi-Fi standards, which continually evolved with greater enhancements of 3 factors; “Throughput”, “wide-range coverage”, and “ease of use”. The standards that are available are 802.11a, b, g, and n, which all operate on an unlicensed frequency band of 2GHz, 3.4GHz and 5GHz. The standard 802.11n was outstanding as this met a satisfactory speed of data rates of up to 600Mb/s, which was comparable with the wired networks, such as Ethernet (cable) Choi et al., (2014). A study conducted by (Verma and Lee., (2011)) stated that demand for increasing wireless speeds and usage are critical as the bandwidth consumed by large file transfer and the streaming of HD (High Definition) quality videos are increasing rapidly. This implied that the 802.11n is inefficient to handle the high demand of data throughput and later, the IEEE 802.11ac standard was developed, exceeding data rates of 1Gb/s (Gigabits per second), also operating on a frequency band of 5GHz avoiding the interference from the 2.4GHz band as a substantial amount of devices sharing the same frequency band.

With the advantages offered such as, ease of installation, devices can be connected where wire installation is not feasible, therefore making wireless cost-effective, attractive and flexible as users are not restricted in one location. Users are able to roam within the wireless coverage. From the advantages of wireless network (Yin and Cui, 2011) have stated that companies are convinced by the convenience offered.

On the other hand, (Bulbul et al., 2008) defined that experts predicted security to be a major drawback and this was because wireless networks travel via radio signals through the air which, penetrates through walls and is not confined to one area. Li and Garuba, (2008) had emphasised the vulnerability of wireless networks as signals can be intercepted by a hacker with a malicious intent. In contrast, a wired LAN can only be intercepted if the wired media was “tapped”, which requires a hacker to be located within the infrastructure. Moreover, it is essential to illustrate the threats faced of utilising wireless networks, as “non-specialists” IT users are unaware of the severe consequences.

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2.2 Wireless Security Human Factors and Technical Factors

From the paper “Wi-Fi Networks Security and Accessing Control” it was stated that current researchers are looking for authentication and encryption algorithms to ensure that defensive capabilities are in place to provide a complete security solution. This is related to an assertion made by Bhagyavati et al., (2004) that technical factors are to be as important as human factors. This implied that wireless security encryption can only be used in its full potential if users implement them appropriately. In addition, as researches are continuously seeking for advancement in technical aspect of security, Choi et al., (2014) emphasised that usability should be taken into account, and training or education must be provisioned when necessary. To ensure human factors commensurate with technical factors and best security practices are adhered to.

A study conducted by Li and Garbua, (2008) identified that home users utilising WLAN do not configure wireless encryption protocols, thus, implied that users may not have the technical knowledge to implement these security measures or have awareness of malicious threats. This is unacceptable as the increased use of e-commerce and e-services continually rise, users must be made aware of the potential risks of their sensitive data. Moreover, Bishop and Klein, (1995) further supported, that those users who consider their system free from sensitive information does not require security. However, the advancement of wireless technologies has improved on their usability to encourage users in applying appropriate security measures when necessary, therefore should be exploited to prevent successful attacks and most importantly hacker’s capabilities should not be underestimated.

Li and Garuba, (2008) have stated that new enhanced wireless encryption protocols are being made available to the public, a survey conducted at San Francisco had exposed that 421 clients cards and 2287 access points utilised in business networks, 35% of networks found to be insecure and APs values remain at default (AirDefence, 2008). Furthermore, the research revealed wireless networks in the city of New York are significantly weak, 40% of business networks were found to be unprotected and 31% had displayed defaults values (Li and Garuba, 2008). Moreover, Lorente et al., (2015) had found that Dutch users considered their default passwords configured within routers to be secure. The study also outlined that WPA2 passwords generated from weak algorithms were to be insecure and this allowed an intruder to use the same algorithm known to compute the default WPA2 passwords. Also, results showed that vendors which supply the same router have minor modifications of their password. Therefore, routers worldwide are considered to be vulnerable to password recovery attacks. This suggests that notifications of the security vulnerabilities will be beneficial for all wireless network users.

It can be declared that wireless technology continuously evolving will encourage the public in deploying wireless technology and also become part of their daily activities. On the other hand, as wireless threats are also advancing it should be made aware to the general IT users and security experts the importance of wireless security and should not be ignored.

Furthermore, users are also deemed to be the biggest security gap, and it is evident through the discussion above that security training or education should be delivered to ensure uses are capable of implementing their adequate security measures.

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2.3 WEP Weaknesses

A study conducted by Arora, et al., (2012) illustrated that the WEP encryption protocol can be easily and quickly exploited by an inexperienced user. For example, an AP which sends a packet of size 1500 bytes and with data throughput (bandwidth) of 5Mb/s, the limited IVs available will be quickly reused, allowing a hacker to obtain the secret key without effort. Furthermore, with the latest version of 802.11ac available and achieving data rates over 1Gb/s this will allow the reuse of IVs instantly. This implied that WEP is essentially insecure and should not be used as it provides in adequate level of security. Yin and Cui, (2011) had also supported that WEP is proven to be obsolete and insecure, but still commonly used.

From the discussion above, it can be assumed that WEP can be quickly exploited due to its flawed architecture, and inability to provide desirable security in conjunction with the latest wireless version available. Kumkar et al., (2012) demonstrated a technique utilised to accelerate the capturing of valuable IVs called “injection”. The researchers (Yin and Cui, 2011) had described the process of injection technique which was, defined as the “ARP Request Replay Attack”. Firstly, the intruder must capture the valid ARP Request Packet sent from a valid client when attempting to authenticate. Secondly, intruder re-sends the captured request packets to the AP. Lastly, the AP which received the request packets will reply to the client, generating valuable IVs. In addition, the researchers have utilised the tool “Aircrack” which is provided within Backtrack4-rc OS. This further supported the statement made by Walker, (2000) that extending IVs bit size does not provide a satisfactory level of security, as it is demonstrated that within a period of time the key can be obtained.

Throughout this discussion it can be gathered that WEP is indeed insecure and should be made aware to the general public of IT users, in order to encourage them to implement the most efficient up-to-date encryption protocol (WPA2) available and enforcing a security policy suitable to ensure feasible security practices are followed.

2.4 WPA and WPA2 (802.11i) Encryption Technique

Spector and Ginzberg, (1994) defined that encryption is a one-way function. Hence, encryption known to the intruder must encrypt correct password candidate (Pairwise Master Key –PMK) to generate the matching hash value. This implied the advantage of the new encryption scheme used compared with WEP.

Figure 2.1: Hashing Process (Krekan et al., 2012, pp11).

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Findings from Tsitroulis et al., (2014) and Arora, et al., (2012) had confirmed WPA and WPA2 to be the most secure protocols, at present. However it was also illustrated as being vulnerable to a brute-force or dictionary attack. A further study conducted by Krekan et al., (2012), defined two techniques that will either delay or prevent the success of a brute-force or dictionary attack. Firstly, taking advantage of the maximum length of characters allowed for a password, this will result in a high demand of resource utilisation, which may be incapable for an average CPU or GPU processor to process. Secondly, the hashing process (4096 iteration of HMAC-SHA1) of the PSK increases the workload for the processor. Chen and Chang, (2015) also indicated the inefficiency in password cracking utilizing the traditional brute-force method as the encryption mechanism of WPA and WPA2 is highly secure and the requirement of computational power can be intensive.

2.4.1 802.11i Authentication (EAP)

WPA and 802.11i are available in two modes, PSK and Enterprise. Enterprise mode requires an external authentication server which is responsible for managing the organisation’s user credentials (Maple et al., 2006). The 802.1x standard is used in conjunction with the EAP protocol to perform the authentication procedure. Furthermore, there are various EAP authentication types available, MD5 (Message-Digest 5), LEAP (Lightweight Extensible Authentication Protocol), TLS (Transport Layer Security), PEAP (Protected Extensible Authentication Protocol), TTLS (Tunnel Transport Layer Security), and FAST (Flexible Authentication via Secure). Although EAP is outside the scope of this study, it should be notable that MD5 and LEAP are most vulnerable and susceptible to dictionary or brute-force attacks (Sobh, 2013).

2.5 Capturing Four-way Handshake

Lorente et al., (2015) stated, WPA and WPA2 performs the “four-way handshake” as an authentication method and known to be the only vulnerable aspect of both protocols, but client must be connected or attack cannot be achieved, because if no clients are connected the four-way handshake cannot be captured. WPA and WPA2 protocol also allows a third-party (Adversary) to launch a “deauthentication” request packet to the associated client to be disconnected deliberately. This leads to a security drawback for both protocols, and if weak passwords are implemented it can be considered weaker than WEP protocol. In order for intruders to exploit this weakness, the intruder can impersonate the Network MAC (Media Access Control) address (optional) of the client-connected device (router or access point) and then will send a “deauthentication” packet to the valid client, causing device to be disconnected.

Disconnected client will automatically attempt to re-connect with the legitimate router or access point performing the four-way handshake, allowing an intruder to capture the encrypted password file and recovered offline without the client knowing as it will not be performed online (Han, Wong & Chao, 2014). Figure 2.2 overleaf will present a simplified version of an adversary performing the attack.

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Figure 2.2: Deauthentication Attack, (Lorente et al., 2015).

2.5.1 Security Level Rollback Attack

It was made aware that WPA was indeed compatible with the existing WEP devices (Bhagyavati et al., 2004), this was also confirmed by He and Mitchell, (2005) who highlighted that WPA architecture consists of WEP mechanism and further demonstrated by Moen et al., (2004). During the authentication process WPA is assigned a “temporal key” (TKIP) intergrity protocol from the EAP server, and then hashed with the 48-bit transmitter address and a 48-bit IV producing a 128-bit WEP key and a clear text IV as a sequence counter, allowing the intruder to capture the leaked IVs to recover the secret key. This attack is known as the “security level rollback”, which takes advantage of the inappropriate configurations of a user, in conjunction with WEP existing mechanisms.

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Chapter 3

3 Passwords

Kuo et al., (2006) had outlined that many researchers have also developed various authentication mechanisms such as, biometric, one-time passwords (OTP), and graphical passwords. However, (Zviran and Haga., 1999) claimed that text-based passwords remain one of the most common authentication control mechanism in place as it is inexpensive and available on demand without additional hardware resources to function (Spector and Ginzberg, (1994). As Wi-Fi networks continued to grow, this leads to increased business productivity in terms of e-commerce and e-service that required individual users to create unique credentials to identify them as a user. In addition, users often reuse passwords for multiple accounts, suggesting that if a user’s password is known to a third party they may have the privilege to gain access to other accounts, using the same credentials. Organisations often enforce password composition policies which are considered to be resistant to password cracking attacks, however the policies known to hackers can help adversary create educated guesses, and if many user passwords are exploited a pattern may be also identified for future referencing. As a result, the study of creating resistant passwords can be valuable not only to protect wireless networks but personal accounts.

3.1 User Password Creation

When users are creating passwords it is important to ensure passwords are memorable and usable. Strict policies can be difficult for users to create an acceptable password causing frustration and ignorance of password policy (Ur et al., 2012; Yan et al., (2000). Complex passwords are likely to contain more character length and mixture of uppercase, lowercase and symbols therefore, it is difficult for users to memorise such password and more time is required during the authentication stage as users may mistype their password or forget, Komanduri et al., (2011) demonstrated that “basic 16” passwords may take longer to create however, it is more usable than passwords containing a mixture of uppercase, lowercase letters, and multiple symbols (comprehensive). Users will then record their password on paper or electronically, for future reference to prevent inaccessibility of a resource. It can be concluded that passwords complexity does not necessarily entail mixture of symbols, uppercase, and lowercase characters. With the support of this conclusion made we can neglect the use of “meaningless” special symbol characters within our test data to be classified as a complex password. However, a permutation technique discussed below involved the use of special symbol characters to aid in memorability and increase complexity. Keszthelyi, (2013) further supported that length is more important than the use of character set as the “exponential function” (ax) will increase significantly than compared with the “power functions” (xa), where ‘a’ is the length and ‘x’ is the character set available.

Rockyou is a common wordlist discussed throughout many password cracking related studies. However, the structure of the passwords had not been researched, thus Keszthelyi, (2013) had investigated the common pattern followed based on the Rockyou wordlist available, containing 14,344,391 unique passwords after it being cleaned up. It was found

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that users are likely to append digits at the end of their password. While it was concluded a common pattern, it is viable for the author to conduct an attack targeting this pattern. Avoiding typical patterns will increase the security and it was recommended by Keszthelyi, (2013) to create unique patterns which are meaningful for the user for aid in memorability.

With the evaluation of user password creation, the author is able to create a realistic empirical data for testing and also a potential approach for the author when conducting the password cracking experiment stage.

3.1.1 Potential Password Combinations (Simple to Complex Passwords)

It is common for users to believe that applying conditions to passwords will improve the resistance of password cracking. The typical conditions are to contain symbols, uppercase, lowercase and not a dictionary word (Yan et al., 2000). An experiment conducted by Yan et al., (2000) outlined that users are likely to ignore the recommended conditions, and choose weak password due to convenience and memorability. However, Proctor et al., (2002) emphasised that applying the recommended restrictions do not result in significant improvement, but increasing the minimum length of password requirement will provide a more resistant password. The experiment was based on the minimum characters 5 and 8, using the popular cracking tool John the Ripper, 33% of passwords were successfully cracked and increasing the minimum length decreased the rate of success to 17%.This implied that password without additional conditions applied can be resistant with a longer length password because the computational power required is directly proportional to the increased length (958 ~ 9563, possible password candidates (Chen and Chang., 2015)). This achieved increased security and memorability as researchers Simon, (1974) and Miller (1956) demonstrated that users are likely to memorise large parts of information, hence, password with increased length also increases the usability and memorability.

A comparison of password-composition polices was studied by Komanduri et al., (2011), the two policies tested were “comprehensive8” and “basic16”. Prior to the experiment, according to NIST password guideline (Burr et al., 2004), comprehensive8 and basic16 were both considered to provide same entropy. However, the results from Komanduri et al., (2011) proved that basic16 has more entropy and usable, contradicting the NIST statement.

Komanduri et al., (2011), also expanded that this measurement of entropy does not provide accurate indication of the resistance against a password crack and mentioned that John the Ripper is not an optimal solution for testing as it is used for short passwords. Therefore, it would be valuable to undertake an experiment involving both password-composition policies, against other password cracking techniques to define if the higher entropy will correspond to a more resistant password crack.

3.1.2 Mnemonic Password VS Regular Passwords

In 2000, an experiment conducted by Yan et al., (2000) demonstrated mnemonic passwords to be secure. Later, in 2006, a further study based on mnemonic password strength was conducted by Kuo et al., (2006) and concluded that mnemonic may not be as secure due to

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the common phrases users have chosen, this allowed hackers to generate a possible mnemonic wordlists.

From the above, Tsitroulis et al., (2014) stated that WPA and WPA2 are vulnerable against brute-force and dictionary attack. However, Kuo et al., (2006) claimed that mnemonic passwords are not detected by dictionary attacks. Hence, it can be assumed that mnemonic passwords may be more resistant than regular passwords. A study was conducted by Kuo et al., (2006) compared the strength of mnemonic passwords and regular passwords. Three password cracking techniques was used against the regular passwords, which are basic dictionary attack, dictionary attack with permutations and brute-force attack and, the tool used was John the Ripper. In order to crack mnemonic type passwords the three techniques used for cracking the regular password was not appropriate. Therefore, Kuo et al., (2006) had made the assumption that users will use common phrases extracted from song lyrics, literature, movies, etc., to create passwords. This allowed the researchers to produce an appropriate “mnemonic-dictionary” which consisted of 400,000 words. The results had illustrated mnemonic passwords to be more resistant as the cracking rate was lower. However, the size of dictionary compared to John the Ripper was three times smaller, which implied that if mnemonic wordlist was effectively the same size, results would be more accurate and valid. Kuo et al., (2006) expanded that mnemonic passwords could be of potential if passwords are not derived from common phrases that can be easily found on the internet, and also benefits as free from dictionary attacks. This provided the author of a potential password rule that could be implemented for testing, to simulate real-life scenario passwords.

3.2. Password Meters Ur et al., (2012) and Schecter et al., (2010) had identified the inconsistency of password strength meters deployed in various websites. For example, yahoo.com and yahoo.co.jp would display a different score for the same password. This misleading result can lead to the question to be asked, “How reliable are password strength meters available?” Therefore, passwords implemented in password meters can be recorded, and then tested against a traditional brute-force or dictionary attack. This can provide an approximate answer to determine the accuracy of a password meter. Using the password can be of benefit to the author to provide an indicator of a simple or complex password (values to distinguish between a simple and complex password are discussed below in Chapter 4.

3.2.1 Measurement of Password Strength

Ur et al., (2012) defined the term “guessability” as being resistant to a password-cracking attack to determine the strength of a password. In order to determine the strength and a guess-calculator was used to identify the amount of guesses required to crack the password. It was claimed that guessability provided an accurate measurement of password strength than the common metric entropy (Weir et al., 2010). From this the author can distinguish what passwords are considered as simple or complex, then implemented into the testing environment to determine the effects, if any, between the passwords tested. However, it is

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infeasible to use this metric as a measurement because it will be carried out during our experiment. Thus, “My1Login” and “The Password Strength Meter” discussed in Section 4 are used to provide us with approximated values of the estimated time to crack and the strength of password measured in percentage. Although, password strength meters were found to be inconsistent, two dissimilar meters are used to validate their strength.

It is assumed difficult to distinguish between a simple and a complex password, as previously discussed, that increasing the length of the password could provide enhanced resistant password against brute-force or dictionary attacks, however, words that are contained within the dictionary of 8 characters will still be cracked effortlessly. In addition, it was previously mentioned by Tsitroulis et al., (2014) that attacks are only successful if it is contained within the wordlist utilised by an attacker. According to this statement, password policies enforced can only provide guidance to create a unique password that is presumed less likely to be predicted by a hacker. A password can be cracked in a matter of time, dependent on the intelligence of the hacker’s pre-computed wordlist. For example, Schechter et al., (2010) illustrated proactive password measures implemented in websites are inconsistent and passwords which are tested against organisation’s wordlist can only prove to be secure “in-house” but cannot be proven secure against outside hackers.

3.3 Alternative Password Cracking Methods

Several studies discussed above revealed that a user’s wireless device security configuration tends to remain at default. Therefore, Mavardiris et al., (2011) demonstrated a successful attack on a router with a default SSID displayed password was also assumed to remain default. Consequently, the router’s password format was known to eliminate the impossible password candidates. A program called “crunch” was utilised to generate the appropriate wordlist to be tested. This demonstration confirmed the statement made by (Lorente et al., 2015), that passwords are typically left at default, when their default SSID is displayed. The knowledge gained from this technique is valuable for user’s awareness that default passwords are known to others, their network can be easily “broken”. Moreover, this should be emphasised further to prevent networks at risk for all wireless network users, at home or large and small enterprises. Although, the technique may not be ideal for the purpose of this project, but the knowledge gained from building an effective (meaningful) wordlist can be of great value.

A traditional password cracking attack is dictionary-based, which hashes words within a dictionary and previously cracked passwords (wordlist) and compares the encrypted hash file until a match is found, or if wordlists does not contain password then, program such as oclHashcat used for our experiment will be exhausted. However, Krekan et al., (2012) demonstrated it was ineffective against a password, with two words concatenated. Therefore, the brute-force attack would be utilised with a new statistical approach developed. The new statistical approach utilises the Markov modelling technique to compute “meaningful” combination of characters and offers additional options to speed up the cracking process (Narayanan and Shmatikov, 2005; Krekan et al. (2012)). It was also previously identified from a study undertaken by, (Yin and Cui, 2011) the password “MyPassword” did indeed consumed more time to run the wordlist and dictionary-based attack was unsuccessful as concatenation may be unpredictable for a hacker and excluded from the wordlist used. It is important to notice that the time metric does not indicate the strength of the password if a

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dictionary-attack is launched as this is just the time required to run through the wordlist comparing the hashed password file with the hashed wordlist candidates. Also the time will vary depending on the dictionary file size and the speed of the processor. From the experiment conducted by Krekan et al., (2012) which utilised the ATI HD 6850 GPU providing a speed of 40,000 passwords per second, it was informative for the author to seek for an adequate GPU meeting the same performance. The author had purchased the GEForce GTX 660ti, which provided similar performance statistics, further discussed below.

Later, Krekan et al., (2013) conducted another investigation utilising the same statistical approach as above, targeting Slovakia language probable passwords and findings illustrated that this method was 15 times quicker in cracking 8 character passwords, than compared with common brute-force and dictionary attacks. According to (Florencio and Herley, 2007) and (Duggan et al., 2012) it is unrealistic to test “meaningless” password candidates, as the resource utilisation will be too intensive to perform the password-cracking program (Krekan et al., 2012). This implied the inefficiency of utilising large dictionary files with meaningless passwords, as memory consumption is very high. Chen and Chang, (2015) introduced a “rule-based” method which improved the cracking efficiency with aid of a GPU processor, achieving a 68% success rate. The unique aspect differs from previous studies as empirical data utilised are real encrypted passwords. Findings concluded by Chen and Chang, (2015) demonstrated the vulnerability of realistic Wi-Fi protected passwords utilised are insufficient, therefore, it would be worthwhile to conduct an experiment to emphasis the level of security between a simple and complex password against an brute-force and dictionary attack, and used as an awareness for the public and I.T professionals in selecting secure unique passwords. Networks broken into can lead to major consequences if not protected with care.

From the discussion of various password cracking techniques available, it will be of value for the author, as a meaningful and logical approach can be formulated prior to performing the experiment. Although, rule-based approach was considered to be most effective password cracking technique, rules can be created to meet our specific requirements and purposes. However, programming knowledge of the author was limited to create a satisfactory rule, to meet our requirement. Moreover, pre-written “rules” were available within the program utilised and tested to be most-effective was also used against our testing scenarios.

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Chapter 4

4. Methodology

The purpose of this section is to present further detail of the primary research used in this experiment. It will address why the primary method for this project was the most appropriate, specific details on how it will be carried out and the future stages involved in the completion of the report.

4.1Primary Research Method

In order to contrast between the two wireless security encryption protocols WPA and WPA2, both protocols will be implemented with the same test data, (simple and complex password scenarios). The time taken to recover the password, and success or failure of a password crack will be recorded for comparison. However, the main focus of this study is to test the resistance between a simple and complex password against a brute-force or a dictionary-based attack.

Various password composition policies are followed to create a simple password and a complex password to compare the resistance by recording the total time taken and success or failure of each attack. Based on the Chapter 3, Section 3.1.1; 3.1.2; 3.2; 3.2.1 the information gained, will allow the author to create realistic password scenarios to reflect the issue of the reality. All passwords created and used as test data must meet two main factors, which are usability and memorability to simulate as closely as possible to a real-life scenario.

In Section 2.5.1 which discussed the exploitation of WPA, as this architecture is compatible with WEP existing devices and the mechanism consists of utilisation of IVs. Therefore, it can be assumed WPA is definitely more vulnerable than WPA2 and the key will certainly be recovered, as gathering adequate IVs can be achieved based on Section 2.3 within the literature review (Chapter 2) discussion. Therefore, recording the data packets communicated and the total time required capturing the four-way handshake for both WPA and WPA2 encryption protocol are necessary to determine if both protocols influence the level of security provided, as WPA uses TKIP and WPA2 uses AES. Thus, it can be assumed that WPA2 will require more time and data packets to be captured in order to successfully attain the four-way handshake, because AES is more secure and through the discussion in section 2.5.1 it is assumed WPA is easier and quicker to crack consisting of WEP mechanisms, also previous researchers emphasised that WEP could be cracked under 60 seconds (Walker, 2000).

A recent study undertaken by (Chen and Chang, 2015) had demonstrated the uniqueness of their study as the empirical data collected are real user passwords, which differs from previous studies that generate a set of random passwords for testing. However, this study motivated researchers to also collect real encrypted password files from other countries. But this is unfortunately impracticable for an Honours project for the author to conduct. To reflect as closely as possible to the real-life scenario, the study of user’s attitude in password

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creation, memorability and usability was fundamental aspect to be taking into account when creating passwords used as test data because passwords must not only meet either a simple or complex requirement but must be easy to use and remember to ensure results are reliable and valid.

Therefore, user’s behaviour when creating passwords was researched in Section 3.1 to simulate a real-life password composition policy users are likely to adhere to. Various password composition policies were followed and no particular pattern was followed to allow us to record a more widespread set of results for analysis also, to make aware for the audience that variety of memorable and usable password composition polices are available with no particular pattern reducing the success of a password cracking attempt.

4.2 Intended Experiment

Within this section an appropriate diagram will be constructed to illustrate the topology used for this experiment along with the necessary configurations and test data (simple and complex passwords) that will be tested.

4.2.1 Construction and Configuration of Topology

In order to conduct this experiment a topology must be configured within a suitable environment, with the appropriate equipment supplied. The necessary equipment required is:

2 x PC (Personal Computer) with Wireless Network Interface Card (WNIC).

Valid connecting client PC A will be represented by a laptop device (Lenovo ideapad U430 touch) with the ready built-in WNIC, Intel® Wireless-N 7260 used to connect with the valid AP wirelessly. Adversary PC B will be represented by another dedicated machine operating the Kali Linux OS (on the bare-metal of the machine without virtualisation) with the requirement of an external WNIC adapter. TL-WN722N is the model number of the external WNIC, although the chipset “AR9271” is the fundamental aspect of the card which supports the promiscuous (monitor) mode discussed below, which allows us to conduct the experiment.

1 x WAP (Wireless Access Point) WPA and WPA2 encryption protocol must be available.

The Belkin enhanced wireless router was chosen, with the WPA and WPA2 encryption protocol available, also can be configured to act as a WAP. In this case, the WAP functioning as an AP will not allow a client to connect to it without an IP address within the same subnet, thus, client devices are required to be configured with the IP address within the same subnet to meet this requirement.

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1 x PC with a GPU processor compatible with oclHashcat program.

GEForce GTX 660ti is the GPU processor selected, manufactured by NVidia and the machine will operate on the Windows 7 OS, with the essential ‘ForceWare’ 346.59 driver installed to instruct the oclHashcat program to use the GPU installed.

The equipment listed will be constructed as shown in Figure 3. Computer A will act as a valid user connecting wirelessly with the Access Point (AP). Computer B will be acting as an Adversary which is within the lab-based environment, which can detect and intercept the wireless communication channel between the valid user and AP –this is achieved via the external WNIC and using the program pre-installed within Kali Linux, including the ‘ath9k_htc’ driver compatible with the AR9271 chipset to monitor efficiently of the wireless communication and performing the necessary attacks. Therefore, further research out with the Literature Review researchers Mohamed and Kaplan, (2015) stated that the WNIC implemented must support monitor mode to conduct this experiment and continued research on the Aircrack-ng suite allowed the author to conclude the correct WNIC to purchase. WPA and WPA2 can only be exploited if 4-way handshake is captured indicated within Section 2.5. In addition, PCs provided within the lab environment have Windows OS pre-installed. However, the current OS does not provide the author the fundamental tools required to conduct this experiment.

It was concluded from the Literature Review Section 2.3 the OS utilised was Backtack4-rc. From the study conducted by Vishnoi and Shrivastava, (2014) Backtrack distribution has been replaced with Kali Linux (Version - 2016.1- at the time of writing).

Vishnoi and Shrivastava, (2014) further expanded that a user utilising Kali Linux must have root privileges in order to utilise the tools effectively, and it is recommended to be installed under the hypervisor named VirtualBox (Version – 5.0.14 – at time of writing) to ensure execution of tasks will not affect the host machine, (in terms of performance and security). Although, it was suggested that Kali Linux was to be installed as a guest-operating system under the Windows 8.1 pro host OS, this was not followed due to the technical issues occurred during the process of this experiment. Firstly, the ath9k_htc driver was not found within the Kali Linux repository which prevented the wireless chipset adapter to function. Secondly, the command “airmon-ng” displayed the correct driver available, therefore, it was

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Client PC A(Lenovo laptop)

Wireless Access Point

Adversary PC B (Kali Linux machine)

Figure 4.1: Experiment Topology.

assume to operate, and the command “airmon-ng start wlan0” was used to set the WNIC into monitor mode which then did not operate efficiently, preventing the author to proceed further, due to the inconsistency and slow performance – wireless networks detected was inconsistent, which could occasionally be detected (within range). This problem was researched extensively and various approaches were followed to tackle this issue, though it did not solve the issue. It was concluded through experience that the virtualisation software was unable communicate (pass-through the instruction) the host USB adapter to operate the AR9271 chipset correctly – From the use of simulation software it was proved that issues occurred would result in inaccurate results, which was be avoided for reliable and valid results to answer the research question. An alternative approach was required, which was to “burn” the Kali Linux ISO file onto a CD-ROM then installed on the machine as “bare-metal” instead of a hypervisor. This not only resulted better performance but the compatibility issues of the AR9271 chipset and the ath9k_htc driver was solved. Throughout the experimentation set-up phase of installing Kali Linux OS as a hypervisor using a virtulisation software virtualbox, it can be concluded that the statement stated by Heidemann et al., 2000 can be confirmed, that virtualisation software utilised could lead to unrealistic and inaccurate results.

Based on the Section 3.3 it is beneficial to utilise the GPU processing power as the WPA and WPA2 encryption mechanism consist of intensive computational power especially, WPA2 with Advanced Encryption System (AES) mechanism used to hash the password utilised, the encryption technique was previously discussed in Section 2.4 and Figure 2.1 illustrated the amount of hashing involved. The two GPUs available within GCU Laboratories are GTForce 745 GTX and Quadro K600 which are both compatible with the oclHashcat program, operating in Windows OS. On the other hand, password cracking is known to consume large amount of time in practicing and running the experiment. It was viable to purchase a GPU in advance and installed on a machine at home to gain more time to practice on demand. The GPU purchased was GEForce GTX 660ti which reaches the equivalent performance standard utilised in (Krekan et al., 2012) study which they had conducted, thus it is assumed to be sufficient for this project.

As mentioned above it is necessary to configure IPv4 (Internet Protocol Version 4) addresses for the constructed topology (as shown in Figure 4.1). This will allow for association between client devices and the AP, also easier identification of each device and ensure that devices are not connected to any external networks such as the internet, as this experiment is solely for experimental purposes and does not involve human participants. Thus, does not require ethical considerations or approval. Table 4.1 will outline the IP address used.

Table 4.1. Assigned IPv4 Addresses.

Devices IPv4 Address Mac Address

Client PC A 192.168.2.64 84:B1:53:CA:35:92

Adversary PC B 192.168.2.128 48:51:B7:C9:49:81

Wireless Access Point

192.168.2.254 00:22:75:C5:95:5C

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4.2.2 Implementation

To contrast the effects (if any) between the two wireless security encryption protocols WPA and WPA2, the password scenarios (simple to complex) will be tested respectively and also different password composition policies will be implemented to determine the resistance of each password scenario (simple to complex) against a brute-force or a dictionary-based attack.

WAP selected will have two available modes for the purpose of this experiment, which are WPA-PSK + TKIP and WPA2-PSK + AES. These two modes will be enabled in turn with each password scenario implemented and also configured on the valid clients to ensure client and WAP are associated (Arbaugh, W., 2002). Various password-composition policies available are discussed in Section 3.1.1; 3.1.2 which will be applied when creating different password scenarios. The common password-composition policies are basic8, comprehensive8 and basic16, which will give the author guidance in creating potential passwords as test data for our experiment – we are not limited to the 3 password composition policies. Moreover, the passwords created will need to be distinguished between simple and complex. Hence, the discussion in Section 3.2; 3.2.1 had demonstrated an evaluation technique to verify the password strength using a password strength meter. On the other hand, it was concluded that password meters may result in inconsistencies, thereby providing inaccurate feedback. To overcome this issue we will validate each created password against two dissimilar password strength meters for a more reliable result, named “The Password Meter” and “My1login” to classify a suitable category for the passwords created. The Password Meter scores passwords from 1% to 100%, while My1login rates them by estimated time period in cracking the password, (in units of time – seconds, minutes…days, weeks, months and years etc). Passwords which score between 0 and 50 (%), or take less than 1 month to crack will be defined as simple, whilst passwords which score between 50 and 100 (%), or take longer than 6 months to crack will be deemed as complex. Values chosen to indicate the strength of each password scenario are displayed by the password strength meters, which will, therefore be validated after this experiment to determine the trustworthiness and accuracy it provides, answering the question of which password strength meter is more accurate, as a question out with the research question. The score of each password will be recorded for later analysis to determine if password meters provide a viable evaluation of password strength shown in Appendix A.4.

Each password scenario will be tested in sequential order from the most simple to complex passwords, implemented in WPA-PSK (+TKIP) and WPA2-PSK (+AES) respectively. All password scenarios will be hashed by the encryption mode enabled and an encrypted hashed password file will be generated. This encrypted (password) file will be captured by the author to launch a brute-force or dictionary attack to crack the password, using their oclHashcat program. Based on the literature review, Section 2.5, a simplified diagram (Figure 2.2) was shown to illustrate the process of capturing a four-way handshake. This four-way handshake will contain the encrypted password file required. As Krekan et al., (2012) stated the encryption technique to be one-way, meaning it cannot be decrypted (computed) to the original password, the only method to crack the “hashed” password file is to encrypt the possible password candidates with the WPA and WPA2 encryption method then compare the hashed candidate files until a “match” is found. If password cannot be cracked the program will be exhausted

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The following procedure will be conducted using the Adversary’s PC B to capture the four-way handshake packets containing the encrypted password file. The tools utilised will be supplied within the Kali Linux OS distribution known as ‘Aircrack-ng suite’ (Kumar et al., 2012). The commands used in the CLI are;

airmon-ng – this will set the adversary WNIC to monitor mode with the identification of which driver was appropriate, in this case ath9k_C.

airodump-ng – wireless networks will be detected by the adversary’s WNIC and the targeted network (Belkin_c5955c) is the broadcasted default SSID displayed (Appendix A.2, Figure 2.6). When the targeted network has been found it will display the necessary metrics such as Beacons, data, channel number and MAC address. The channel number was manually configured to ‘12’ to reduce the chances of interference with other wireless networks affecting our results.

aireplay-ng – In order to reduce the time taken to capture the (WPA) four-way handshake aireplay-ng command was used to intentionally send deathuentication packets to the valid client, which disconnects the associated client to force them to re-authenticate entering their password (PSK). Hence, this attack is only successful if a valid client is connected to the wireless network, because the four-way handshake must be captured to precede the password cracking attack procedure.

At first the four-way handshake, also known as WPA handshake captured during the user authentication stage entering the PSK. This file will be captured as a ‘.cap’ format created by Aircrack-ng suite, therefore, it is necessary to convert the file format to ‘hccap’ for the oclHashcat program to understand the captured file, as this will be utilised in order to crack the “shadow” (encrypted) password file. Two methods can be used to achieve the packet conversion.

Firstly, the oclHashcat official webpage offers the facility to convert the captured handshake file. However, the file size must not exceed over 5MB (Megabytes), which a second alternative method was used, supplied within the Aircrack-ng suite ensuring the files remain consistent and “clean”.

Secondly, the file must be cleaned (removing any unwanted excess data also reducing the file size) using the command:

wpaclean <out.cap> <in.cap>

Lastly, the file can be converted using the command within Aircrack-ng to ensure file remains consistent and error free. The command used at this stage is:

aircrack -J <ConvertedFileName.hccap> <Location of the .cap File>

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The converted hccap password files will be saved onto a USB memory stick (Adata-16GB) that will allow the author to conduct the password cracking process offline, utilising the machine with the GEForce GTX 660ti GPU installed.

Due to the limitations of the PCs within the GCU lab environment the password cracking process will be undertaken “in-house” dedicated machine operating a Windows 7 OS with the required GPU processor (GEForce GTX 660ti) implemented on the physical machine available to increase the speed of the cracking process. The PC will require the correct GPU driver (ForceWare 346.59 or later – at the time of writing) to instruct the oclhashcat program to exploit the graphics card capabilities. To perform the password cracking procedure, the commands will be executed on the Windows OS and the user must run the CLI as ‘administrator’ to avoid permission interruptions.

This experiment is considered to be purely practical and therefore, the author will conduct further research (if necessary) on blog posts and other relevant materials available on the internet to gain more experience utilising the CLI with the associated commands. While learning and investigating the commands and attacks available within the official hashcat website a GUI (Graphical User Interface) of the oclhashcat program was found, written by an outsourced team named BlandyUK, which was recommended by various members of the hashcat forum. The hashcat GUI 1downloaded was the version 0.45b1 (at the time of writing). Prior using the GUI oclhashcat, the driver (ForceWare 346.59 or later – at the time of writing) downloaded will consist of two applications 64 bit or 32 bit to operate the GUI. This must be located within the “binary” field of the program to be operational, also the 32 bit application was chosen due to the compatibility issues with the Windows CLI permissions. On Figure 3 the application file can be identified at bottom of the GUI application. This was assumed to be limited with the capabilities offered compared with the CLI, therefore it was used alongside with the CLI as the GUI was able to provide the commands of the attack which was modified to suit the user’s needs.

Each encrypted password file will be compared against a suitable ‘wordlist’ which contains English dictionary words and a set of previously cracked passwords, discussed in Section 3.3. This list allows a user to edit or create appropriate wordlists to increase the chance of cracking each password scenario. In addition, the hashcat GUI brute-force attack offers the user (Author), to mask specific rules to eliminate the unrealistic passwords, utilising resource efficiently. Wordlists, such as ‘real-human_phil2’ and ‘Rockyou3’, can be found on the internet via a simple Google search.

Once the oclHashcat program has run, a list of metrics will be displayed on the CLI window. Metrics of concern in this project will be the total run time of success and the success or failure of the attack. Also the speed at each hashed password candidate is being compared with per second (however, the speed of the GPU will only be noted to determine the speed of operation as this value does not impact the research question to be answered). Although the total run time will be recorded, this will only be recorded if the attack is successful. The reason is because the total run time will dependent on the size of the dictionary wordlist used until it is exhausted and total run time to test the number of possible password combinations user has set. This implied that recording the time metric will not indicate how strong a password can be as this can vary depending on the hacker’s intelligence and resources they

1 https://hashkiller.co.uk/hashcat-gui.aspx2 https://crackstation.net/buy-crackstation-wordlist-password-cracking-dictionary.htm3 https://wiki.skullsecurity.org/Passwords

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implement. Throughout the experiment it can be concluded that the conclusion made above in Section 3 that passwords can vary depending on the hacker’s intelligence, thus, the results concluded will not guarantee to be resistant against all hackers. On the other hand, it is worthwhile to demonstrate for general and professional I.T users the possible password patterns available to increase the complexity without decreasing the factors memorability and usability, providing a more secure network.

To evaluate the comparison between WPA and WPA2 protocol, the metric of concern will be the number of “data packets captured.” Within Section 2.3, it was concluded that the valuable data to be captured to crack WEP was the IVs gathered. Furthermore, it was stated at Section 2.6 that security roll back was achievable against WPA as it utilises WEP mechanisms. As a result, it can be argued that recording the data packets required to capture the four-way handshake will distinguish the differences, if any between the both protocols of concern WPA and WPA2. Moreover, packet injection attack can be launched to increase the amount of required IVs to crack WEP. Although this attack cannot be used against protocol WPA2, an alternative command was used, which was the aireplay-ng command to purposely send deauthentication packets to the valid client to capture the four-way handshake. This implied that the total time metric can be varied due to the attack (deauthentication) being launched by the attacker and also any client connecting to the AP is unpredictable. The time variable was not included within results as it does not provide valuable data for the research question to be answered, but included within the appendix for additional information.

All metrics will be concluded in a table format with the results generated and including the password strength rating (Appendix A.4) from the password meters. All results will then be ready for final evaluation.

4.2.3 Password Scenarios (Test Data)

Table 4.2 illustrates the password scenarios (test data) derived from the Section 3 and further reading, with regards to user behaviour in creating, storing, usability and memorability of various password types. All passwords chosen are assumed to be memorable and usable, indicated by Keszthelyi, (2013). During the password creation phase, the common password rule such as, “do not contain a dictionary word” was not followed because previous literature Ur et al., 2012 & Yan et al., (2000) emphasised that passwords with increased length to be more secure than passwords with conditions of, must not be a dictionary word, must be minimum of length 8 (this was a requirement as WPA encryption requires minimum 8 character length), must contain lowercase, uppercase, digit and symbols. Therefore, this suggested that as long as password produced met an adequate length (i.e from 10-12 characters) it was considered as secure. However, to ensure memorability and usability dictionary words are definitely easier to remember than a mixture of characters. In addition, the results concluded by Chen and Chang, (2015) outlined the typical password pattern used which was valuable when creating passwords to achieve memorability, simulating to a real-life case study.

There are a variety of existing wordlists available consisting of dictionary words (referring to English dictionary words for the purpose of this project), previously cracked passwords from diverse websites such as UNIX, Myspace and Facebook. This implied using any dictionary-based words as passwords to be highly insecure. Therefore, for the purpose of this experiment

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it is likely for a user to choose dictionary words with additional characters also meeting the “simple” password requirement and preventing straight-forward dictionary attacks. Furthermore, no particular pattern was followed in password scenario creation, although various techniques was used such as “permutation” (substituting ‘s’ for ‘$’ or ‘5’) and words such as ‘I’ and ‘hate’ written in slang and text-messaging style ‘aye’ and ‘h8’ respectively. It can be concluded from Table 1 that passwords are likely to be in lowercase and include digits, less likely to include symbols. The password ‘My_Password’ (Number 4, Simple) was similar with scenarios 2,3,8,9, and 10, but including capital letters at typical position stated by Zviran and Haga, (1999) also a underscore (‘_’) symbol was included to decrease the possibility of being cracked. In order, to produce results to reflect the real-life issue of weak passwords vulnerability, password scenarios was not just created to satisfy the simple requirement but considered to be of realistic choice. To satisfy the realistic choice the typical passwords such as ‘qwerty’, ‘abcdef’, ‘987654321’ were all avoided as it was previously cracked and also meaningless.

Table 4.2. Test Data: Simple and Complex Passwords.

Simple password candidates Complex password candidates

1) pa$5word 1) Shakespeare1was5born6in4Avon2) crack16me 2) Luv2Laff3) life2short 3) LaCPaS1KMS4) My_Password 4) SWMEteMy$$5) hell0w0rld 5) 20Caledonian166) police999 6) S1125113GCU7) 01413313000 7) aye<3pb&j8) ice-cream 8) Ipmdt@18yo9) ayeh8school 9) P@5$W012d10) love&hate 10) protekMYwhyfi

From the comparison between the simple and complex password scenarios shown on Table 4.2, it can be concluded that complex passwords do consist of more complexity such as increased length, symbols and uppercase characters, also positioning of the characters are considered unique to assist in memorability. Furthermore, Komanduri et al., (2011) results concluded that password composition policy comprehensive8 was more difficult to create, but when created it remained usable as the confirmation of password rate was lower than basic16. On the other hand, passwords which met the comprehensive8 conditions was used in conjunction with other methods such as permutation, mnemonic and “phonetic” replacements to help memorability and Shay et al., (2010) conducted a study which emphasised that users found complex passwords usability to be inconvenient, but was still used as it provided them increased security, ensuring usable factor was met. Password scenario 1 within the complex category was considered most resistant as the number of characters contained was high, although this was highly memorable and usable as the pattern used was memorable and did not consist of complex symbols and meaningless data as, Shakespeare was born in Avon during 1564 with each digit represented the space. Therefore, without foreknowledge of the passwords it was impractical to brute-force due to resource limitation. Password scenario 7 and 8 utilised the mnemonic and unique symbol ‘<3’ representing love within the sentence, “I love peanut butter and jelly” with I being replaced with the slang written form ‘aye’ as

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discussed above, and first letter of the sentence used. Scenario slightly varied as this did not contain unique use of symbols but did contain an uppercase letter ‘I’ within a typical position. Overall, this is assumed to be resistant as identified by Kuo et al., (2006) within Section 3 suggesting that mnemonic passwords to be secure as phrases are not extracted from famous or common literature, poem and movies etc. The most vulnerable passwords created within complex scenarios are 5 and 6 because it does not involve unique variations and symbols, therefore, it is more likely to be brute-forced, and also in scenario 6 it also contains a dictionary word, suggesting it is more vulnerable. Password scenarios 2 and 10 can be considered similar as the password created was a phonetic replacement to avoid being vulnerable against dictionary attacks and the location of digit used for scenario 2 uncommon, this was used again to avoid the chances for adversary to predict the located characters. Moreover, the capitalised word ‘my’ within the scenario 10 was chosen, again to avoid being predicted by an adversary, as previous literature reading defined that passwords used typically include capital letters at the beginning or end Keszthelyi, (2013).

4.2.4 Password Cracking Approach

It was discussed by researchers Chen and Chang, (2015) that it was impractical to use dictionary attack as wordlists file can be large, consuming terabytes of space, and also standard processor are incapable of processing the wordlist of large size. This statement was taking into account during the password cracking experimenting stage, therefore only appropriate wordlists was searched for ensuing the file size was practical i.e. below 1GB (Gigabyte) and contained a high cracking rate of previously cracked passwords. Later, a wordlist named “realhuman_phill” was downloaded (legally for experimental purposes only) from cracking-station webpage. This was considered as an appropriate wordlist because members of hashcat had recommended this to be an effective wordlist file, which contains common human passwords, from the success of this attack it could also be used to validate that the password scenarios used are realistic, reflecting a real-life case study. In order to ensure the wordlist file was efficient as possible the wordlist was simply edited using Microsoft word 2007 utility to remove the unwanted password candidates, reducing the file size to 683MB (Megabytes) with 63768655 password candidates contained within the wordlist.

Once the wordlist file was prepared it was simply added into the wordlist library of the hashcat GUI. On the application there are several tabs available the “Wordlists & Markov” tab was selected, and then the “Add Wordlists..” button will be clicked to locate the wordlist file to be added, in this case the realhuman_phill.txt will be added into the library. Appendix A.3 will demonstrate how to add a wordlist into the library.

When the wordlist was added the dictionary based attack can be launched using the “straight” mode provided by the GUI. Figure 4.3 illustrates how the dictionary attack was launched for all the password scenarios tested, and the success or failure of the attack will be displayed and discussed later, in Section 5. Figure 4.3 defines the “Hash File” field, this required the converted four-way handshake file in format “.hccap” for this application to understand the hashed password file.

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Figure 4.3: Launching Dictionary-Based Attack.

It can be easily identified that the “Hash Type” field chosen was “WPA/WPA2” to ensure the correct password candidate will result with a matched hashed value the same as the captured four-way handshake.

Simple password scenario number 7 was undertaken with the knowledge gained from Section 3.3 that common passwords are likely to be home telephone or mobile telephone numbers. The brute-force attack mode was selected with the option to mask the specific rules to eliminate the unrealistic combinations, as brute-force attack attempts to try every possible combination, and this would be impractical. Therefore, local telephone numbers beginning with ‘0141’ indicating the area and number ‘331’ specified the location of the area. While this masks eliminated the 7 possible characters of a password the remaining four digits can be brute-forced, until all possible digit combinations are tested.

Figure 4.4 outlined the appropriate configurations configured to launch the brute-force and mask attack combined together.

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Click this icon to locate the hashed password scenarios in “.hccap” format.

The attack mode selected.

32 bit application to allow the GUI to be operational.

Figure 4.4: Local Telephone Mask and Brute-Force Attack Configurations.

The success or failure of the attack will be displayed later within Section 5.

The method of combining masks and brute-force attack was modified for different occasions. As a Caledonian student, the student matriculation number was assumed to be unique therefore, it would be logically used with additional characters which are meaningful to help memorise the password and ensuring it was usable. The mask set was ‘S11’ with 5 remaining digits which was restricted between 1 to 5 to eliminate and decrease the amount of combinations created, also the three letters GCU was prefixed then appended in turn for each test. The three uppercase letters were decided as this is highly logical and memorable for a user to help memorability and the pattern of the three letters were concluded from study conducted by Kesztheyi, (2013), that users are likely to prefix or append digits and uppercase characters within a password.

Throughout the research conducted it was seen regularly that the word “password” was often modified as a password to increase the complexity, therefore, possible permutations discussed by Kesztheyi, (2013) and Zviran et al., (1999) was used in order to eliminate the impossible permutations. Again, this technique was considered as Chen and Chang, (2015) rule-based approach. The remaining letters such as p,w, and d which was not considered to be permutated. Consequently, the remaining letters was varied from lowercase to uppercase through each test ran, and the successful configurations are shown Figure 4.5.

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The mask used.

Figure 4.5: Possible Permutation Based on Typical Passphrase “Password”.

It was previously discussed that programming knowledge was required to create a suitable wordlists for the purpose of this experiment. However, this was unviable to learn for the student due to the limited time allocated. Thus, pre-written rules available for use, this was supplied within the GUI hashcat program, and was considered to be most effective by Blandyuk, the creator of the hashcat GUI application. Although this was rated to be effective, this is subjective against the password scenarios tested. However, the rules were used in conjunction with our wordlist files, and the total run time required was impractical i.e. 85 days. This implied that our GPU processing power was incapable to handle the rule-based approach, and should be investigated further with a processor with an enhanced performance machine, such as a cloud computing environment utilising multiple GPU processors at once.

Figure 4.6 demonstrates the rule-based attack window with the rule implemented for testing.

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The pre-configured charset characters to be brute-forced with the mask used.

Figure 4.6: Rule-Based Attack.

An output window of the CLI running is also shown in Figure 4.7, which estimated that 85 days will be required for the test to be completed.

Additional methods was applied in order to crack the password scenarios such as combinator rule, which combines two wordlists (either unique or same) to generate possible password candidates to be tested, supplementary rules can also be applied in conjunction with this attack known as the left and right rule. This additional rule allows certain characters to be placed in between the two dictionary wordlists file known as the left rule, and also the right rule allows the user to place a defined character set at the end of the right hand-side of the wordlist used. For example, wordlists containing the words car and bike, a left rule could be applied such as “-“ character therefore, the new generated password candidate will be “car-bike” or “bike-car” if the right rule with a defined exclamation mark was implemented then the new password candidate will be “car-bike!” or “bike-car!”

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The rule-based file that have been loaded for testing.

Figure 4.7: Rule-Based Total Time Estimated To Be Run.

Chapter 5

5. Results

Within this section the metric of value discussed in Section 4.2.2 were gathered from the finished experiment outlined in Section 4. The results were critically analysed and displayed appropriately with additional commentary to help the reader interpret the definition of each results. Therefore, we can use the results to prove or disprove our hypotheses identified in Section 1.2.4, in relation to answer our research question of interest based on the findings concluded with further discussions.

5.1 Four-Way Handshake (Data) Packets

For WEP encryption protocol, the capturing of Initialisation Vectors (IVs) will allow the secret key to be obtained through the leaked IVs, causing WEP to be broken. With new architecture built in WPA and WPA2 this is not achievable as the key is not “static”. Consequently, the capturing of IVs will be meaningless to distinguish the difference between protocols WPA and WPA2. In order to compare the difference between both protocols, the metric “data packets” captured was used to evaluate for any differences. Data packets are also known as the “four-way handshake packets” and this was a valuable metric because WPA and WPA2 are only vulnerable against a password cracking attack which entails the hacker to obtain the shadow password file by capturing the password while authenticating, if no client is connected this cannot be achieved as mentioned in Section 2.5. For the purpose of this experiment a client was always connected, and a deauthentication attack would be launched to intentionally cause the client to re-authenticate to capture the wanted data. Furthermore, it was discussed within Section 4.2.2 that the time metric to be excluded as this can be varied by the user due to the time the deauthentication attack being launched or when a client wished to connect. Therefore, the time value could not provide valuable evidence to distinguish the differences, if any. Although the time was recorded for interest found within the Appendix A.5.

From the hypotheses H3 identified in Section 1.2.4 WPA and WPA2 was assumed to have no notable difference between the two protocols, although the protocols WPA and WPA2 consisted of different encryption mechanisms, TKIP and AES respectively. Although both protocols are different the encryption bit size used are also different. AES used an encryption bit size of ‘256’ and TKIP used an encryption bit size of ‘128’, it was also previously mentioned that AES was computational intensive which we are lead to believe more packets should be required to obtain the secret password. From the experiment conducted by Yin and Cui, (2011), it was concluded that encryption bit size varied in WEP protocol to cause no significant effects. Therefore, it motivated us to find the differences between protocols WPA and WPA2, if any.

In order to evaluate the protocols WPA+TKIP and WPA2+AES equally both password scenarios, simple and complex was implemented accordingly for both protocols and the data packets captured and the time recorded can be found within the Appendix A.5, as the average values for each data captured are displayed for a vivid presentation.

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Figure 5.1 illustrates the average values of the data packets captured for simple passwords implemented in WPA and WPA2 and, Figure 5.2 presents the average values of the data packet captured for complex passwords implemented in WPA and WPA2.

5.1.1 Comparison between WPA and WPA2 Data Captured

As can be seen in Figure 5.1 it was identified that WPA2-PSK required more data packets to be captured than with WPA-PSK protocol, with the simple password scenarios implemented for both protocols. We will continue our evaluation for the complex password scenarios implemented in both protocols.

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Figure 5.1: Data Packets Captured in WPA and WPA2 with Simple Password Scenarios Implemented.

Figure 5.2: Data Packets Captured in WPA and WPA2 with Complex Password Scenarios Implemented.

However, Figure 5.2 with complex passwords implemented in WPA and WPA2 protocols resulted in opposite findings from Figure 5.1 where WPA-PSK gathered more data packets than compared with WPA2-PSK.

Evaluating the results of Figure 5.1 and Figure 5.2, we can confidently say that both protocols and their encryption bit size (WPA+TKIP and WPA2+AES) do not have an effect on the total data packets required to be captured. Proving our hypothesis H3 to be true and the answer can be valuable to the general public and IT specialists that encryption bit size for WEP, WPA, and WPA2 are not influenced at all. Moreover, a notable change was revealed due to the simple and complex password variable, which will be further discussed below.

In Figure 5.2, results indicated an average figure of approximately 1250 data packets being captured, which increased greatly the amount of data required to be captured for WPA and WPA2 with simple password scenarios implemented. Although the quantity of data packets captured for WPA2 was not as high as WPA with complex password scenarios deployed, it was worth outlining that it still required more packets than with both protocols with simple password scenarios. This revealed that simple to complex password variables influence the quantity of data packets to be captured in protocols WPA-PSK and WPA2-PSK. Also, from the hypothesis H2 mentioned at Section 1.2.4 and conclusion from Yin and Cui, (2011) that complex passwords required more IVs to be obtained to crack WEP than with simple passwords, then this provoked the question to be asked which was, “how does the quantity of data packets captured vary, with regards to the simple and complex passwords implemented in WPA and WPA2. The two remaining figures are presented appropriately to distinguish the results clearly to outline the variance of data being captured in WPA-PSK and WPA2-PSK due to the simple and complex scenarios deployed. Firstly, Figure 5.3 will confirm that complex passwords requiring more data packets to be captured than compared with simple passwords for WPA-PSK. Figure 5.4 will also confirm the hypothesis H2.

5.1.2 Simple Password Scenarios VS Complex Password Scenarios Implemented in WPA and WPA2

The results displayed on Figure 5.3 clearly showed that complex passwords definitely do require more four-way handshake (data) packets to be captured for the secret key to be gained. As previously discussed it was concluded that encryption protocol and bit size do not have an effect on the data captured results, however, both scenarios was tested for accurate and viable results, and Figure 5.3 demonstrated the results for WPA-PSK. Simple password required an average of just under 600 packets captured, and for complex passwords approximately 1250 packets was captured.

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In Figure 5.4 illustrated the results for the WPA2-PSK encryption protocol against the two variables simple and complex password scenarios. The results again claim that more data packets are required to be captured with complex passwords implemented regardless of the protocols being utilised.

From the results presented above it can be confirmed that complex passwords do require more packets to be acquired when a more complex password is implemented for protocols WPA, WPA2, and also WEP does require more IVs to be captured when a more complex password is used. It can be asserted with confidence that hypothesis H2 is true, although it was identified by Tsitroulis, (2014) that complex passwords do not require more data packets to be captured. Furthermore, the password “Icecream” was tested in WPA2 and required a total of ‘22792’ packets to be captured (Tsitroulis, 2014), and in our experiment a similar password “ice-cream” was tested and required a total of ‘322’ packets to be captured (Data Packets can be found in Appendix A.5). Both passwords are highly similar but the total amount of data captured is incomparable, therefore the password “Icecream” was entered into the password strength meters to determine the password strength. The feedback provided by both password strength meters defined it to be very weak. It can be assumed that the equipment used were dissimilar causing results to be inaccurate, since the OS, Kali Linux was an enhanced version of “Backtrack4-rc,” this may have experienced inconsistencies during the packet capturing phase, causing it to acquire more data. In addition, both external wireless network cards used a different chipset, and the signal powers supplied by each WNIC are different which must also be further investigated for a satisfactory answer. Unfortunately, this was out the scope of this study and could not be investigated but recommended for future work. To further expand, in our experiment a complex password of “Shakespeare1was5born6in4Avon” was implemented in WPA-PSK and acquired ‘692’ data packets, then a simple password was entered into WPA-PSK and this required a total of ‘1955’ data packets. With the comparison between one simple and one complex password it cannot be justified that our hypothesis is not true. Despite, the technical factors, we summarised the test data of Tsitroulis, (2014) “raw data” and an averaged (data captured) value of ‘15,458’ was calculated, then comparing with our averaged data captured results with simple passwords. This strongly confirmed that our hypothesis H2 is true.

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Figure 5.4: Data Packets Captured in WPA2-PSK against Simple and Complex Password Scenarios Implemented.

It was worthwhile to present the summarized data of Tsitroulis, (2014) study, as the difference in with our results of WPA2-PSK complex scenario, the values was much higher. Therefore, a graph was created for easier identification, shown below, Figure 5.5.

It can be concluded that mixture of uppercase, lowercase, digits and special symbol characters impact the variance of data packet capture, as the complexity of the password would be greatly increased. From our study the metric “entropy” was mentioned as an alternative method in measuring password strength, this is calculated based on each individual character which makes up the password, it would be suggested that entropy to be used to determine the correlation between the entropy and the data packets captured for a more precise result.

5.2 Variance of Security Due to Simple and Complex Password Scenarios

The focus of this project is to answer the research question stated in Section 1.2.2. In Section 4.2.3 the simple to complex password scenarios is presented in Table 1 which is clearly separated into appropriate categories with the feedback provided by the password strength meters applied. The motivation of this study was to emphasise the insufficient level of security provided by “weak” (simple) passwords that are typically chosen by an IT user, regardless of the education or background due to convenience, usability and memorability factors, which are prioritised before security. As a result, in order to reflect the real-life scenarios, and provide informative guidance in creating usable and memorable passwords without losing security, the password scenarios used as test data are considered to be realistic and unique. From previous studies, all passwords tested were either weak or too complex for a realistic user to use. This encouraged us to demonstrate how complex passwords can provide a satisfactory level of security without losing memorability and usability factor.

In order to contrast the level of security between a simple and a complex password the success or failure of the password cracking attack against each password scenario is recorded,

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Figure 5.5: Comparison between Tsitroulis, (2014) summarised results with WPA2-PSK Complex Password Scenarios of Averaged Data Packets Captured.

and is included within the Appendix A.6. The time variable was only recorded due to the success of the attack, as the failure of the time does not impact the significance level of security provided, as discussed in Section 4.2.2.

5.2.1 Comparison between Simple and Complex Passwords Implemented in WPA and WPA2

To contrast the difference between only simple and complex passwords fairly, both password cracking results was presented in two separate graphs. Firstly, Figure 13 displays the results of simple and complex passwords implemented in protocol WPA-PSK. Secondly, Figure 14 is used to illustrate the between simple and complex passwords when implemented in WPA2-PSK. Figure 5.6 and Figure 5.7 is also used to validate the hypotheses H1, mentioned in Section 1.2.4.

It is easily identified in Figure 5.6 that simple password scenarios achieved a higher rate of success against password cracking, than compared with the complex password scenarios, when implemented in WPA-PSK

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Figure 5.6: Success and Failure Rate of Simple and Complex Password Scenarios Implemented in WPA-PSK + TKIP

Similarly, Figure 5.7 is used to present the rate of success against a password crack when simple and complex password scenarios were implemented in WPA2-PSK protocol.

Hypothesis H1 cannot fully be claimed true, as Figure 5.6 and Figure 5.7 only demonstrates that complex password success rate to be lower than compared with simple passwords. Section 5.2.2 will present the results to prove or disprove hypothesis H1.

In conclusion, the results illustrate that complex passwords are more resistant against a password cracking attack, than with simple passwords as it is considered more difficult to guess, especially if no valuable information of the users are unknown.

Although passwords, “crack16me”, “My_Password”, and “ayeh8school” was not cracked in our experiment this cannot be justified as secure as previously discussed that passwords are only as strong as a hacker’s intelligence, in other words, if one hacker cannot guess the password, another existing hacker may have a greater knowledge and experience to guess the password used. This also suggests that results obtained in our experiment are difficult to compare with other studies as their intelligence, wordlist and equipment utilised are unique. For example, Tsitroulis, (2014) used a complex password of “WwWbontokk@@@anka1290nayY%” which was cracked in their experiment conducted, and a simple password scenario used by Yin and Cui, (2011), “love&peace” was not cracked. It is positive that password cracking success to be unpredictable. Furthermore, complex password scenarios, “LaCPaS1KMS”, “Ipmdt@18yo”, and “SWMEteMy$$” are mnemonic based type passwords, which is not effective against a normal wordlist used in our experiment, and mnemonic wordlists were not available online. However, the structure and techniques used can be of valuable guidance for the IT specialists or ordinary IT users.

5.2.2 Comparison between WPA and WPA2 protocols against Simple to Complex Passwords

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Figure 5.7: Success and Failure Rate of Simple and Complex Password Scenarios Implemented in WPA2-PSK + AES

In Section 5.2.1 it is concluded that simple passwords are definitely easier to crack than compared with complex passwords, as simple passwords created do not consist of unique structure and use of techniques as described in Section 3.1, 3.1.1, and 3.1.2. To fully answer the research question stated in Section 1.2.2, it is important to compare the success and failure rate against WPA and WPA2 with simple and complex passwords implemented.

We can see that Figure 5.8 compares the difference between WPA and WPA2 with simple password scenarios implemented, and the results clearly reveal that both protocols achieve the same success and failure rate. This implies that WPA and WPA2 do not affect the password cracking attack launched in this experiment, which is demonstrated in Section 4.2.4.

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Figure 5.8: Comparison between WPA and WPA2 with Simple Password Scenarios Implemented.

Figure 5.9 also compares the difference between WPA and WPA2, if any. However, this shows the corresponding results as seen in Figure 5.8 but with complex password scenarios implemented in both protocols. It can be concluded that WPA and WPA2 do not impact the password cracking attack launched.

The results presented in Section 5.2.2 clearly confirmed that hypothesis H1 to be true and outlines that WPA and WPA2 do not influence that password cracking attack launched. Although, in the Appendix A.6 the time of success between WPA and WPA2 shows minor difference this was considered as negligible.

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Figure 5.9: Comparison between WPA and WPA2 with Complex Password Scenarios Implemented.

Chapter 6

6. Final Discussion and Conclusions

This section will provide a brief summary of the project to emphasise the issues required to be addressed, and how our experimental results concluded within Chapter 5 will be of value for the expertise in this field, and others. Our findings are used to validate the hypotheses tested and answer the research question. Project limitations were faced during the experimental phase, and are all identified with the further work to be undertaken to develop a more efficacy project.

6.1 Summary of Project

With wireless networks increasing significantly in large enterprises and for home users, it is important to alert the users, the vulnerabilities of wireless networks and the consequences if their networks are not properly secured. As technology continuously evolves, wireless performance capabilities are also enhanced. For example, the data throughput rate can achieve up to 1Gb/s. From Section 2.3, WEP was claimed to be insecure due to its weak RC4 algorithm architecture and its re-use of IVs, taking into account the weaknesses and the data throughput rates achieved in today’s wireless transmission, WEP will be cracked instantly. Therefore, this had driven us to investigate the advanced wireless encryption protocols WPA and 802.11i (WPA2). It was clearly outlined by Tsitiroulis, (2014) that WPA and WPA2 are susceptible against password cracking attacks, if weak passwords are implemented. We discovered that users are likely to select weak passwords due to convenience, memorability and usability, sacrificing the level of security provided. Therefore, it is important to differentiate the level of resistance provided by simple and complex passwords for the general IT users and specialists. Although users often believe that complex passwords consists a mixture of uppercase, lowercase, digits and special symbols, this was disproved by Burr et al., (2004). A variety of techniques discussed in Section 3 can help users create a usable and memorable password without losing security, which was also used as test data shown on Table 2. Throughout the researching phase, simple to complex password scenarios used as test data were cracked. On the other hand, this should not lead the user to believe that simple and complex password to provide equivalent security level. This then motivated the user to use passwords which are realistic to simulate real-life scenarios which led to the research question:

How does the level of difficulty vary according to simple and complex passwords utilised against a brute-force or dictionary attack on a system, when implemented into the wireless security protocols WPA and WPA2 (802.11i)?

For the question to be answered, the user’s behaviour and attitude in creating passwords in concern with memorability and usability will be investigated. An intensive investigation based on various passwords types was fundamental to create realistic passwords to reflect a real-life scenario. Passwords must also be separated between into a simple or complex category to emphasise the variance in terms of security level provided, which was validated using two dissimilar password strength meters for accurate feedbacks. All simple and

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complex password scenarios were created as test data, and then implemented into WPA and WPA2 encryption protocol in turn, and then attacked with either a brute-force or dictionary based attack. After conducting the experiment, the results were presented in Section 5 to help critically analyse the impact between a simple and a complex passwords and the differences, if any between WPA and WPA2, with regards to the research question to be answered, along with the objectives and validation of hypotheses. The aim of this project is to educate the users in selecting resistance passwords with respect to memorability and usability, without decreasing security.

6.2 Discussion of Results

6.2.1 Research Question Findings & Hypotheses

The status of the following hypotheses identified in Section 1.2.4 will be discussed further with regards to answering the research question outlined in Section 1.2.2.

H1: Complex passwords will be more resistant against a brute-force or a dictionary-based attack, than compared with a simple password implemented in WPA and WPA2 encryption protocol.

Results: Confirmed

From the results concluded within Section 5.2.1 and Section 5.2.2 it is evident that simple password scenarios implemented in WPA and WPA2 achieved a higher rate of success, 70% for both protocols tested, where complex password scenarios achieved a success rate of 20%. This implied that simple passwords are more vulnerable than complex passwords regardless of the encryption protocol enabled, because complex passwords involve more thought and time to guess. Various techniques were provided in Section 3 to assist users in creating memorable, usable, and complex passwords to encourage users to select secure passwords without difficulty in memorising. Although, it was indicated in Section 3.2.1 that passwords are only as strong as the hacker’s intelligence and the wordlist applied, meaning that passwords not contained within the wordlist or cannot be guessed by a hacker the password is safe. With respect to this statement if password complexity is subjective and cannot be guaranteed that all complex passwords to be “un-crackable” but should provide greater resistance against password cracking attacks.

An example to confirm the above statement, the predicted time provided by My1Login (password strength meter) for the password ‘P@5$W012d’ (complex password scenario 9) was 7 months, this was cracked within zero seconds. Although the time taken to crack refutes the feedback given, this was due to the intelligence of the hacker, eliminating the unrealistic password candidates as discussed in Section 3.3 to improve the attacking efficiency. The mask applied is shown on Figure 5 and the reason for this password to be easily cracked was due to the typical substitution of characters such as ‘a’ being replaced with ‘@’, ‘A’ or ‘4’.

It can be suggested for the audience that common dictionary words applied with permutation is deceiving as hackers are ordinary users, suggesting that hackers may apply the same method, which has been discussed above. Therefore, users should think outside the box, to avoid the passwords being predicated easily. It is also evident from Figure 5.7 and 5.8 that

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wireless protocols do not impact the security level, but users are advised to deploy WPA2, as WPA can be cracked using the security roll back attack discussed in Section 2.5.6 due to the WEP mechanisms within WPA architecture. From Section 2.2, it was revealed that large enterprises uses default passwords provided by organisation and also with WEP enabled. For example, an education institution with weak passwords caused major consequences with the valuable data gained by a third party, suggesting the sensitivity of data should be commensurate with the complexity of password to gain satisfactory security.

H2: Complex passwords are assumed to be more resistant against password cracking, than compared with simple passwords. Therefore, more four-way handshake (data) packets are expected to be gathered from a complex password scenario than compared with a simple password scenario.

Results: Confirmed

It was concluded by Yin and Cui, (2011) that complex passwords required more data packets to be captured when attacking WEP. Therefore, it is assumed that complex passwords will require more data packets to be captured than compared with simple passwords implemented in WPA and WPA2.

Findings from Section 5.1.2 illustrated that complex passwords required more data packets to be captured than compared with simple passwords, regardless of the protocols enabled. Approximately 614 data packets more were required for complex passwords than compared with simple password which required only 586, when implemented in WPA-PSK, shown in Figure 10. Figure 11 again confirmed hypothesis H2 when WPA2-PSK was enabled, with average value of 839 packets to be captured for complex passwords and 638 packets captured for simple passwords.

A similar study was conducted by Tsitroulis, (2014) which was contrasted with our data captured results of WPA2-PSK with complex password scenarios implemented only, to avoid bias results - although findings discovered WPA and WPA2 to have no notable difference. Figure 5.5, again confirmed our hypothesis H2 and also demonstrated the impact complex password made up of random digits and symbols to require greater consumption of data packets to be captured. An assumption was concluded that passwords with greater length and containing symbols were to require more data packets to be captured, hence a difference of approximately 14,000 packets data captured.

It can be established that complex passwords are more resistant than compared with simple passwords from the confirmation of this hypothesis as more data is required to be gathered. More data packets implied a larger shadow password file, and packets could be affected during the capturing phase leading to a false WPA handshake capture. This suggests that the four-way handshake is more difficult to obtain when complex passwords are implemented.

H3: WPA+TKIP and WPA2+AES will be cracked utilising the same method. Thus, it will have no or negligible difference between both protocols, when cracking the password scenarios, simple to complex.

Results: Confirmed

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It was previously identified that WPA and WPA2 both utilise different encryption mechanisms TKIP and AES respectively. AES was also known to be more secure as it is computation intensive, and uses an encryption bit-size of 256 bits, were TKIP uses a size of 128 bits. However, Yin and Cui, (2011), revealed that encryption bit size does not impact the security when cracking WEP, which suggests no notable difference in WPA and WPA2. Therefore, our results presented in Section 5.2.2 proved that hypothesis (H3) to be true, as the attack launched against WPA and WPA2 with simple and complex password scenarios, achieved the exact same success and failure rate. With simple passwords achieving a success of 70% with regards to WPA and WPA2, and a failure rate of 30%, shown in Figure 5.8. Figure 5.9 demonstrates the success and failure rate of the attack when complex passwords implemented in WPA and WPA2, achieving 20% of success, and 80% of failure.

As the processing power continuously evolves, it should be made aware to the network engineers that brute-force and dictionary attacks will become easier, thus, enhancing the hashing process of WPA (displayed in Figure 2.1) can increase the time required and the processing capabilities a hacker requires. While this does not solve the root of the problem it should be made aware the processing power available in today’s world.

6.2.2 Limitations and Further Works

Knowledge of programming was insufficient to create specific rules applicable for the chosen GPU, as the pre-written rules available were infeasible for the GPU to handle as stated in Section 4.2.4. Although, other rules were used it would provide a more accurate result for the audience of how resistant our complex password scenarios are if tested thoroughly. Furthermore, it was demonstrated by Tsitroulis, (2014) that complex passwords (i.e WwWbontokk@@@anaka1290naY%) was “crackable” with the use of a supercomputer. Therefore, it would be recommended to exploit the advanced cloud computing services available to launch the password cracking attack, as the processing capabilities can compute a greater amount of possible password candidates for testing. It was outlined in Section 3.3 that real-encrypted password files were extracted from streets for testing, to emphasise the vulnerability of weak passwords chosen by users. Therefore, it is valuable to conduct a study extracting real empirical data from a different continent. However, it was mentioned in Section 4.1 that time allocated was inadequate. This had driven us to create realistic passwords from simple to complex, with the knowledge derived from Section 3.1, 3.1.1, and 3.1.2. The password scenarios were created by the author, which may lead to bias, unfair results when launching the password cracking attack. For example, the complex password scenario ‘S1125113GCU’ may be regarded as bias due to the specific target on student’s matriculation identity number.

In order to achieve accurate results it would be suggested to request other participants to create a password which they have not used and all personal details must be excluded to avoid unfair results.

The wordlists applied when cracking complex password scenarios could be considered as unfair as the wordlists are only effective against passwords made up of dictionary words –simple password scenarios, which the majority of the complex passwords were able to avoid. Although it can be considered to produce inaccurate results, it is also beneficial to distinguish

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the level of effort required to crack a simple password as compared with a complex password. In future, “mnemonic” dictionary types should be applied with the use of a supercomputer or cloud system, for rigours testing.

From the discussion above it can be concluded that the passwords are only as strong as a hacker’s intelligence or the wordlist applied, also confirming the statement made by Tsitroulis, (2014) that password are only successfully if wordlist contains the password wished to be cracked. WPA and WPA2 were known to be vulnerable when weak passwords are used, and can only be cracked by capturing the four-way handshake (Pre-Shared Key) as discussed in Section 2.5. This vulnerability can be avoided if wireless access point devices have the intelligence to reject de-authentication packets launched by a hacker, when attempting to capture the targeted client WPA handshake. On the other hand, this proposed idea can only prevent connected clients to re-authenticate, this cannot prevent the four-way handshake being captured if new clients wish to connect whilst a hacker is patiently waiting for an victim to connect.

6.2.3 Advantages

Initially the simulation software (or hypervisor) “VirtualBox” was intended to be used to install the Kali Linux OS, operating as a guest operating system. This was considered as a cost-effective approach, but inconsistent reception of wireless signals were found due to the driver issue in communicating with the host USB (Universial Serial Bus) to instruct the external WNIC, as discussed in Section 4.2.1. To avoid this issue another physical machine was used with Kali Linux OS installed on the bare-metal. As a result, performance in WNIC was also enhanced. Therefore, capturing the four-way handshake was consistent and free from errors.

6.4 Conclusions Remark

The focus of this project was to differentiate the impact of security level in relation to the simple and complex passwords used in a wireless network encryption protocol (WPA and WPA2). Extensive literatures were researched allowing the development of an appropriate experiment methodology reflecting as closely as possible to the real-life scenario. For example, one study retrieved empirical data from the streets of Taiwan, thus motivating the author in using realistic passwords as test data (simple to complex password scenarios), rather than randomly generated meaningless passwords. An appropriate research question was generated along with the relevant hypotheses, which then led to the results detailed in Chapter 5 and 6.2.1.

From the results gathered and concluded within Chapter 5, it would be informative to raise the awareness to not only the IT Security professional, but to the general public that utilises passwords to protect their assets. As the use of wireless networks is increasing rapidly with a diverse range of users, it is vital to warn the users of the risks they may face if assets are not protected with care. Hackers can exploit their weaknesses and commit crimes to steal valuable personal details, such as bank account passwords to escalate their privileges. Therefore whether your device contains sensitive data or not, it should be protected as strictly as possible, as hackers ability cannot be underestimated which can cause unpredictable damage. This project is of value as it was indicated in Section 2.2 that users are not aware of

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the consequences, as users typically believe that data contained within the system does not require a secure password. Users who follow this statement are the priority targeted audience. As human factors must commensurate with technical factors, network engineers must improve on the encryption protocol as identified in Section 6.3.1.

It is also evident from the extensive research undertaken that the protocols WPA and WPA2 are relatively secure due to the intensive hashing involved, illustrated in Figure 2.1. However, enhanced processing capability creates a disadvantage for users, as hackers are able to exploit the processing power to compute possible password candidates in a shorter period. For example, in this experiment a (GEForce GTX 660ti) GPU allowed us to compute approximately 40,000 hashes per second, which is far more superior than a high-end CPU (i7 processor) which achieves speeds up to 2000 hashes per second (Krekan et al., 2012). Further evolution of cloud computing services can improve the processing capabilities exponentially as a cluster of computing hardware devices can unite as one, calculating possible password candidates simultaneously. Therefore, security experts and network engineers could increase the intensity of hashing involved, but this will not solve the root problem.

Hackers are able to send de-authentication packets to a WAP causing legitimate users to re-authenticate, to gain their PSK (hashed password file). If the WAP does not allow the acceptance of false de-authentication packets then, the technical aspect of WPA and WPA2 are assumed to be secure against any password-cracking attacks launched. In order for a hacker or any third party to gain a users’ password, alternative attacks must be made aware for the audience such as, social engineering, shoulder-surfing and key-logger programs (to record the keys entered by a user).

In Section 6.2.1, the confirmed hypothesis H3 revealed that WPA and WPA2 to have no significant effect against password cracking attack launched. On the other hand, previous literature outlined the possibility of “security rollback attack” on WPA, indicating that alternative attacks against WPA are to be weak. Thus, WPA2 should be used wherever possible by home and small or large enterprises with complex passwords to gain full potential of the WPA2 encryption protocol.

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