6 ways to build an insecure mobile application

© Copyright 2013 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.

6 ways to build an insecure mobile application Daniel Miessler Principal Security Architect, HP Fortify June 2013

© Copyright 2013 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. 2

Agenda

• Introduction

• Why mobile security matters

• Mobile security differences

• Common mobile vulnerabilities

• Takeaways

• Questions


Introduction

Daniel Miessler, CISSP, CISA, GCIA Principal Security Architect, HP Fortify

• 10 years experience doing security testing

• 5 years experience doing appsec testing

• Web Application Vulnerability Assessments

• Mobile Application Vulnerability Assessments

• Application Security Process Development

• Enterprise Security Consulting

[email protected]

mailto:[email protected]


Why mobile security matters


Data from Smart Insights, Yankee Group 2012

Considerations: Mobile traffic increases

• Global mobile data traffic will increase 26-fold

between 2010 and 2015

• There will be nearly one mobile device per

capita by 2015 (~7 billion)

• Mobile payments will exceed 984 Billion

by 2014


Considerations: Mobile ubiquity

• Mobile performance is becoming

extraordinary

• Using a desktop (static) computer will

become increasingly rare

• “Home computer” will come to mean better

input and display options


Considerations: Mobile ubiquity II

• Mobile computing will soon be known as

“computing”

• Computing somewhere other than your

mobile device will be the activity that

requires a name

• Attackers follow the users


Considerations: Mobile insecurity • Mobile development is the hottest type of

development right now. New surface area equals dangerous surface area

• If anyone’s going to put features over security to get the product out the door, it’s likely to be a mobile team

• Many enterprise mobile developers haven’t had the security training that other types of developers have had

• Many assume that because mobile back ends aren’t visited directly they are more secure (obscurity assumption)


Mobile security differences


Q: What’s the difference between “regular” security and mobile security?



Client

Mobile security differences: Thick-client testing

Server

• ABAP • C/C++ • Java • Objective C • Python • VB6 • COBOL • Cold Fusion • XML • SQL

• ASP.NET • VB.NET • C# • Classic ASP • HTML • Flex • JavaScript/AJAX • JSP • PHP • VBScript

Network


Client


Server



• Credentials in memory • Credentials on filesystem • Data stored on filesystem • Poor cert management

Network


Client


Network Server




• Cleartext credentials

• Cleartext data • Backdoor data • Data leakage


Client


Network Server






• Injection flaws • Authentication • Session management • Access control • Logic flaws


Q: What’s the difference between this and mobile?



Client

Mobile security differences: Mobile security

Network Server






• Injection flaws • Authentication • Session management • Access control • Logic flaws


Two key differences

Mobile security differences: Expanded mobile risk

Magnified physical vulnerability

As with most other types of computer, once the attacker has physical access, it’s over

Magnified network vulnerability

Your network traffic is more likely to be visible to others with a mobile device than at work or home


Common mobile vulnerabilities 2013 edition


Common vulnerabilities: OWASP Open Web Application Security Project

• Thought leader in web security

• Runs many projects designed to help industry security their applications

• OWASP Top 10

• Risk Rating Methodology

• Vulnerability Prevention Cheat sheets

• Our team is heading up the Mobile Top 10 2013

http://www.owasp.org/

http://www.owasp.org/


OWASP Mobile Top 10 Risks

M1 – Insecure Data Storage M6 – Improper Session Handling

M2 – Weak Server Side Controls M7 – Security Decisions via Untrusted Inputs

M3 – Insufficient Transport Layer Protection M8 – Side Channel Data Leakage

M4 – Client Side Injection M9 – Broken Cryptography

M5 – Poor Authorization and Authentication M10 – Sensitive Information Disclosure


Common vulnerabilities: Most apps are vulnerable

Most high-scrutiny (see: previously hacked) mobile apps are decently secure now, but the next tier down still have many issues

• Evaluating any given application is likely to yield significant vulnerabilities

• The younger, more eager the shop– the higher the chance of issues


Common vulnerabilities: Real-world perspective

• Definitely check out the OWASP Top 10, but this is more about what we’re seeing in the wild

• We constantly test mobile applications from the top companies in the world, and these are the top categories of issue we find in those applications


Common vulnerabilities: Real-world results

• Case study of 120 Mobile applications for a single enterprise customer (results are typical)

• 66% of applications contained a critical

or high vulnerability that either: • Disclosed 1 or more users’ personal data

• Compromised the backend system

66%


Common vulnerabilities: Logic flaws

Logic flaws are due to faulty developer assumptions, i.e. not thinking like an attacker

• Changing an arbitrary user’s password

• Bypassing multi-step authentication

• Free product by skipping payment step

• Product + refund by submitting negative number

• Defeating a business limit by entering a high negative number

• Getting a bulk discount on only one item by modifying the cart manually afterwards


Common vulnerabilities: Logic flaw defense

Logic flaws are avoided by performing exhaustive vulnerability assessments before going to production

• Fully understand the anticipated flow of the application

• Assume the mind of the attacker

• Identify places that developers likely made assumptions

• Attempt to take advantage of those assumptions

• As a developer, think in terms of abuse vs. just regular use


Common vulnerabilities: Poor TLS implementations

Many mobile developers are allowing SSL communication with any host

• Trusting any certificate it sees

• Allows expired certificates

• Allows trivial MiTM attacks

• Can connect to HTTPS once, and then fall back

• Once in the middle, attackers can model your app’s functionality enroute to breaking it


Common vulnerabilities: Poor TLS implementation

TLS protection has multiple levels of security

• Ensure HTTPS is always enabled

• Attempt to match the name of the remote certificate

• Certificate pinning*

• Recognize that nothing is fool-proof, and adjust according to your app’s specific needs

• Remember that pinning was a defense against compromised CAs, not against MiTM


Common vulnerabilities: Promiscuous client-side storage Perhaps the most abused functionality is client-side storage

• Storage of credentials in plist files, SQLite databases

• Failure to use KeyChain to store credentials

• Storage of sensitive application data on filesystem

• Apps (e.g.: banks) storing their images in the public folder rather than in their sandbox

• Applications logging to the system log, but sending sensitive app data along with it


Common vulnerabilities: Promiscuous client-side storage Q: What data on your iOS device is protected by the built-in encryption, i.e. the passcode?


Common vulnerabilities: Promiscuous client-side storage A: By default, only email and texts. In other words, most application data

being stored on an iOS device is available to anyone who steals your phone—even if it is locked and has a passcode.


Common vulnerabilities: Promiscuous client-side storage

DEMO

• Corporate issued iPhone • Latest software (6.1.4) • Not jailbroken • Locked

• With passcode


Common vulnerabilities: Promiscuous client-side storage Be cautious of anything you save—anywhere—including on the client-side

• Ensure you’re using the platform-recommended solution to store credentials

• Ensure you use the Data Protection API to store any sensitive data; it will not be protected by default: (See: NSFileProtectionComplete in developer documenetation)

• Ensure you are storing everything from your app into the app sandbox so it cannot be read by other applications

• Check all logging functionality and note what you’re sending

• Observe your log files within the XCode log viewer and ensure you are not storing anything sensitive


Common vulnerabilities: Failure to harden binaries

There are a number of binary defenses that developers are not implementing

• ASLR PIE (memory randomization)

• Stack Smashing Protection Enabled (Canary-based)

• Automatic Reference Counting (memory resources)

• Binary debug not disabled – User path information disclosure


Common vulnerabilities: Failure to harden binaries

Use all defenses possible to harden your binaries before release

While some are not critical security issues, they still can have an impact on the overall quality of your application


Common vulnerabilities: Privacy violations

Many applications violate privacy without developers being aware

• Does the application access GeoLocation data?

• Does the application access your Address Book?

• Does the application access your Photos?

• If so, what is your app doing with this data?

• Does your application use analytics engines?

• If so, what does it send there? (UUID, app data?)


Common vulnerabilities: Privacy violations

Go with an absolute least-privilege approach

• Don’t access any data that could be considered private if you don’t need it

• There are applications out there that can evaluate what a given binary accesses (AppAuthority, HP Risker)


Common vulnerabilities: Assumption of web obscurity

A massive number of applications we see and compromise are compromised due to backend vulnerabilities

• Promiscuous web services

• Full SQL statements right in web service calls (saved money on MSSQL Server Manager)

• Blatant SQLi, XSS, CSRF, File Includes, etc.

• Many developers assume “who’s coming here?”

• The datastores are often shared!

• Shared hosting means compromise of multiple customers


Common vulnerabilities: Assumption of web obscurity

Harden your web backend as if the mobile app didn’t even exist

• Remember how easy it is to MiTM a mobile app

• Assume everyone can see your traffic

• This means they can see all the paths and parameters for your backend

• Assume attackers will come knocking

• Consider the risks of shared hosting, as others might not be taking these steps—even if you did


Takeaways


Takeaways

It’s an interesting time for mobile security

• Everyone’s heading to mobile, and the attackers are following

• Mobile is on the leading edge of development, so mobile projects are especially susceptible to security shortcuts

• Most non-scrutinized applications have major vulnerabilities that are easily found


Takeaways


• Think like an attacker and follow some basic steps to help you evaluate your own applications without much cost

• Assume the attacker has access to the device and visibility of all traffic going to and from the server, and code accordingly (learn from cryptography)

• As part of a threat modeling step, track your sensitive data through your app, from user to device to network to server; see where it’s vulnerable

• Don’t store PII if you don’t have to


Takeaways


• Remember that you must explicitly use the Data Protection APIs otherwise your data will still be available to a thief

• Don’t be intimidated by “mobile” security; the fundamentals are the same

• Use industry-tested methods for implementing security; be extremely weary of DIY solutions for input validation, encryption, authentication, etc.

• Take advantage of the resources available to help you, e.g.: platform secure coding guides, OWASP, etc.


Takeaways: Let us help

HP Fortify on Demand • Cloud-based application security testing

• Both static and dynamic testing, using automated and manual techniques

• Integrates with your SDLC and build environment to provide critical security checkpoint

• Single portal for code uploads and reviewing results

• Test your apps for free at: https://fortifymyapp.com


Takeaways

Resources iOS Security Guide http://images.apple.com/iphone/business/docs/iOS_Security_Oct12.pdf

Android Security Guide http://source.android.com/tech/security/

OWASP Mobile Top 10 https://www.owasp.org/index.php/OWASP_Mobile_Security_Project

OWASP iOS Developer Cheat sheet

https://www.owasp.org/index.php/IOS_Developer_Cheat_Sheet

http://images.apple.com/iphone/business/docs/iOS_Security_Oct12.pdf

http://images.apple.com/iphone/business/docs/iOS_Security_Oct12.pdf

http://source.android.com/tech/security/

http://source.android.com/tech/security/

https://www.owasp.org/index.php/OWASP_Mobile_Security_Project

https://www.owasp.org/index.php/OWASP_Mobile_Security_Project




Thank you

Date post:	20-Aug-2015
Category:	Technology
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6 ways to build an insecure mobile application

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