© Centre for Development of Advanced Computing, Hyderabad.

© Centre for Development of Advanced Computing, Hyderabad


Presentation Outline

• Theory about Hacker• Some Common Attacks(Theory)• Buffer Overflow Case Study:

– Buffer Overflow in Microsoft RPC DCOM implementation

Hacking Techniques Demonstration


We believe…

• Think like Hacker, to stop the intrusion in your own Network

• Protect your Network, before they(evil hacker) attack the vulnerabilities in your Network


What is hacking

• Hacking is exploring the details of programmable systems

• Stretching the capabilities of computer systems

• Sharing their computer expertise

• Can also mean breaking into computer systems(cracking)

Hackers saw programming as a form of artistic expressionand

the computer was the instrument of their arts


Difference between Hackers and crackers

• HACKER – A person who enjoys exploring the details of programmable

systems and how to stretch their capabilities, as opposed to most users, who prefer to learn only the minimum necessary.

– One who programs enthusiastically (even obsessively) or who enjoys programming rather than simply theorizing about programming.

– Positive

• CRACKER– gaining access to important information that you have. Surely

you are a V.I.P. in the computer world and you are being seriously hunted;

– gaining access to your system resources.– interrupting your host’s efficiency (with no threat of exposure).

This may be dangerous if your clients require uninterrupted service from your host;

– forming a base to implement the above goals while attacking another computer. In this case, the logs of the attacked computer will show that the attack was performed from your address;

– checking out the mechanism of attacks against other systems. – Negative


Hacking History

• 1969 - Unix ‘hacked’ together• 1971 - Cap ‘n Crunch phone exploit discovered• 1988 - Morris Internet worm crashes 6,000 servers• 1994 - $10 million transferred from CitiBank accounts• 1995 - Kevin Mitnick sentenced to 5 years in jail• 2000 - Major websites succumb to DDoS• 2000 - 15,700 credit and debit card numbers stolen from Western Union

(hacked while web database was undergoing maintenance)• 2001 Code Red

– exploited bug in MS IIS to penetrate & spread– probes random IPs for systems running IIS– had trigger time for denial-of-service attack– 2nd wave infected 360000 servers in 14 hours

• Code Red 2 - had backdoor installed to allow remote control• Nimda -used multiple infection mechanisms email, shares, web client, IIS• 2002 – Slammer Worm brings web to its knees by attacking MS SQL

Server• 2003- MS Blast worm exploited the vulnerability in the MS RPC DCOM

implementation• 2004- My DOOM worm performing the DDOS against MS and SCO web site• ……………………..


Hackers’s Motivations

• Fun• Profit• Extortion• Technical Reputation• Scorekeeping• Revenge/

maliciousness• Intellectual

Challenges

• Desire to embarrass• Experimentation• Self Gratification• Problem Solving• Exposing System

Weakness• Want to be Hero of Wild

Internet


Types of hackers

• Professional hackers– Black Hats – the Bad Guys– White Hats – Professional Security Experts

• Script kiddies– Mostly kids/students

• User tools created by black hats,– To get free stuff– Impress their peers– Not get caught

• Underemployed Adult Hackers – Former Script Kiddies

• Can’t get employment in the field• Want recognition in hacker community

• Ideological Hackers– hack as a mechanism to promote some political or ideological purpose– Usually coincide with political events

• Criminal Hackers– Real criminals, are in it for whatever they can get no matter who it hurts

• Corporate Spies– Are relatively rare

• Disgruntled Employees– Most dangerous to an enterprise as they are “insiders”– Since many companies subcontract their network services a disgruntled vendor

could be very dangerous to the host enterprise


Types of Attacks

• Internal – like Technical attacks• External – like Social Engineering


Without Hackers,

• Programming languages such as C and C++ would not exist

• Operating Systems such as Unix and Linux would not exist

• Microsoft might not been developed• Basically, no one would be designing

new types of software• Antivirus Companies would not have

became billionaire


With Hackers that crack,

• Security is thought of and efforts are put forward to making information more private

• Free software is made available because of these people

• These crackers create jobs for others to stop them

• Since home users are more vulnerable with less security they are an easy target for people to hack into for fun

• Software developers improve their software

Hacking is healthy to the computer industry?


Threats to the Information System

Autonomous Agents, Back Doors, Backup Theft, Call Forwarding Fakery, Condition Bombs, Covert Channels, Cracking, Data Aggregation, Data Diddling, Data Theft, Degradation of Service, Denial of Service, Dumpster Diving, E-mail Overflow, E-Mail Spoofing, Excess Privileges, False Updates, Get a Job, Hangup Hooking, Illegal Value Insertion, Invalid Values on Calls, Induced Stress Failures, Infrastructure Interference, Infrastructure Observation, Input Overflow, IP Spoofing, Logic Bombs, Login Spoofing, Masquerading, MIP Sucking, Network Services Attacks, Backup Information, Open Microphone Listening, Packet Insertion, Packet Sniffing, Password Cracking, Password Guessing, Password Sniffing, PABX Bugging, Phracking, Phreaking, Ping of Death, Piracy, Process Bypassing, Protection Limit Poking, Salami Technique, Scanning, Session Hijacking, Shoulder Surfing, Social Engineering, Spamming, Sympathetic Vibration, Time Bombs, Timing Attacks, Toll Fraud Networks, Traffic Analysis, Trap Doors, Trojan Horses, Tunneling, Use Bombs, Van Eck Bugging, Viruses, Wiretapping, Worms


How Hackers can Access Your Network

WirelessWireless

InternetInternet

DoorDoor ModemModem


Once inside, the hacker can...

• Modify logs– To cover their tracks– To mess with you

• Steal files– Sometimes destroy after stealing– A pro would steal and cover their tracks so to be

undetected• Modify files

– To let you know they were there– To cause mischief

• Install back doors– So they can get in again

• Attack other systems


Some Common Attacks


SYN RQST

SYN ACKclient

server

Spoofed SYN RQST

zombie victim

Waiting buffer

overflowsZombies

SYN ACK

TCP SYN flood


Zombies on innocent computers

Server-level DDoS attacks

Infrastructure-level DDoS attacks

Bandwidth-level DDoS attacks

Distributed Denial of Service


Smurf Amplification

victim

zombie

amp/255.255.255.0

500

victim amp.255 ping.rqst

src dst

1

Direct broadcast address

500500500500


Spoofing

X Y Z

Mr. Z is that you?

Yes I’m here!


Social Engineering

Attacker Devesh

“social engineering is a term that is used by hackers and crackers to denote unauthorized access by methods other than cracking software”

Good afternoon., Is this Mr. Devesh

Yes

Sorry to disturb you. I understand that you are very busy, but I cannot log into the network.

And what does the computer tell you?

“Wrong password.”

Are you sure you are using the correct password?

I don’t know. I don’t remember the password very well.

What is your login name?

Devesh

OK, I’ll assign you a new password… Hmm…let it be art25. Got it?

I’ll try. Thank you.


Passive Sniffing

login:

devesh

passwd:

india123

SNIFFER

In Hub Networks


Active Sniffing

Switch 1 2 3

Port 1- 00:00:00:AA:AA:AAPort 2- 00:00:00:BB:BB:BBPort 3- 00:00:00:CC:CC:CC

00:00:00:AA:AA:AA 00:00:00:BB:BB:BB 00:00:00:CC:CC:CC


How ARP Works

IP -> 192.168.51.35MAC -> 00:00:00:AA:AA:AA

IP -> 192.168.51.36MAC -> 00:00:00:BB:BB:BB

Internal ARP Cache192.168.51.35 – 00:00:00:AA:AA:AA

Internal ARP Cache192.168.51.36 – 00:00:00:BB:BB:BB

Who has 192.168.51.36

ARP Request

ARP Reply

192.168.51.36 is at 00:00:00:BB:BB:BB

A B


ARP Cache Poisoning

IP -> 192.168.51.36MAC -> 00:00:00:BB:BB:BB

Internal ARP Cache192.168.51.35 – 00:00:00:CC:CC:CC

System B

IP -> 192.168.51.35MAC -> 00:00:00:AA:AA:AA

Internal ARP Cache192.168.51.36 – 00:00:00:CC:CC:CC

System A

IP -> 192.168.51.37MAC -> 00:00:00:CC:CC:CC

Internal ARP Cache192.168.51.36 – 00:00:00:BB:BB:BB192.168.51.35 – 00:00:00:AA:AA:AA

Attacker

192.168.51.36 is at 00:00:00:CC:CC:CC 192.168.51.35 is at

00:00:00:CC:CC:CC


Attack Methodology

The Beginning – Goal : Decide why this system should be attacked.

Steps 1. Gather the Information about the victim hosts

2. Locate the victim hosts by some scanning program

3. Identify the victim host vulnerability

4. Attack the victim host via this vulnerability

5. Establish backdoors for later access

6. After break-in, use this victim host to – Install rootkit to cover tracks

– run sniffer to collect user password information

– hack or attack other network

– use this victim host resource to carry out their activities

– Web page defacement for certain assertion


Buffer Overflow

In general, buffer overflow attack involves the following steps:

i. stuffing more data into a buffer than it can handle

ii. overwrites the return address of a function

iii. switches the execution flow to the hacker code


Case Study : Buffer Overflow

• Buffer Overflow Vulnerability in Windows RPC DCOM Implementation


About Vulnerability

• Vulnerability within the Microsoft’s RPC DCOM vulnerability was made public on July 16th 2003– Attackers can execute the code of their choice with system

privilege by exploiting this buffer Overflow problem

• First version of the exploit was released on July 23, 2003 by XFOCUS(Only DOS by crashing the SVChost.exe)

• Second version of the exploit was released on July 25th 2003 by Metasploit (Allow the spawn and binding of the Command shell with system privilege on remote machine)

• Backdoor trojan was found on the affected Machine on 2nd August 2003

• On august 11th the worm known as MS Blast was discovered which infected hundred of thousands of machines within few hours


Reason for Buffer Overflow

• Problem due to unchecked parameter within a DCOM function– HRESULT CoGetInstanceFromFile(

IN COSERVERINFO * pServerInfo,IN CLSID * pClsid,IN IUnknown * punkOuter, // only relevant locallyIN DWORD dwClsCtx,IN DWORD grfMode,

IN OLECHAR * szNameIN DWORD dwCount,IN OUT MULTI_QI * pResults );

• This function is used to create a new object and initialize it from file

• The sixth parameter i..e. szName is allocated a space of 0x20(32 bytes) for the file name– Input is not checked here.

• When a larger value is input, anything beyond 0x20 space is overflowed and then allow the arbitrary code to get executed with system privilege hr = CoGetInstanceFromFile (pServerInfo, NULL, 0, CLSCTX_REMOTE_SERVER,

STGM_READWRITE,

"C:\\1234561111111111111111111111111.doc",1,&qi);


Steps Performed by Exploit Code

Attacker Victim

192.168.51.35(>1024) 192.168.51.36:135

Exploit establishes the connection toTCP port 135 on Victim Machine

192.168.51.35(>1024)

Exploit send the DCE/RPC Bind Request for the file“\\victim\c$\1234561111111111111111111111.doc”to victim machine and uses the buffer overflowto spawn the shell on TCP port 4444

192.168.51.36:135

192.168.51.35(>1024)

Exploits connects to shell on newly opened TCP port 4444 and has the System privilege

192.168.51.36:4444


Recently Announced buffer Overflow Problem in MS

MSASN.1 Vulnerability Could allow the remote code execution

Abstract Syntax Notation(ASN.1) is a data standard that is used by many applications and devices in the technology industry for allowing the normalization and understanding of data across various platform

MSASN1.dll is widely used by Windows security Subsystem.

Announced on Feb 10, 2004 by Microsoft

All the Microsoft OS Platform is affected

Exploit released on feb 14th

But only crash the LSASS.exe service and force the system to reboot Next possible WORM will be under the Development.


Thank You

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