This presentation on Android Security was given for the course "Cryptography & Network Security" at the KU Leuven

1. ANDROID SECURITY
Robin De Croon
Lars Jacobs
|H05D9a| Cryptografie en netwerkbeveiliging: hoorcollege
prof. dr. Ir. Bart Preneel

2. Content
• Introduction
• System and Kernel Level Security
• User Security Features
• AndroidApplication Security
• Recent Security Problems
• Demo
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3. INTRODUCTION
Introduction
System and Kernel Level Security
User Security Features
Android Application Security
Recent Security Problems
Demo
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4. Introduction
• All data located on your smartphone
• Passwords
• Photos
• (Text) messages
• Medical records
• …
• Smartphone cannot trust anyone
• Android secure?
• Open Source  Safer (Hoepman et al.)
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5. Distribution of mobile malware by
platform in 2012
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6. Mobile threats motivated by profit
by year
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7. AndroidVersions
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8. Android Software Stack
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9. SYSTEM AND
KERNEL LEVEL
SECURITY
Introduction
System and Kernel Level Security
User Security Features
Android Application Security
Recent Security Problems
Demo
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10. Apps & Processes
• Own Linux Process + user ID  Sandbox!
•Data is protected from other apps
•Secure IPC
• API calls are authorized according to permissions
• Hardware access is authorized by Group Membership
• Java, Native,WebKit
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11. Bootloader
• Bootloader is locked by default
• Boot process
• Signature check
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12. Memory management
• A lot of memory corruption bugs
 Attacker can control the program
• Improvements
•No eXecute (NX) (since Android 2.3)
•Address Space Layout Randomization (since Android
4.0)
•Position Independent Executables
(since Android 4.1)
•FORTIFY_SOURCE (since Android 4.2)
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13. Randomization in Android 2.3
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14. Randomization in Android 4.0
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15. Randomization in Android 4.1
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16. Rooting
•Default no root access
•Possible through ‘su’ binary
Bootloader unsafe
Root apps can do ANYTHING
Latest versions of Android
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17. USER SECURITY
FEATURES
Introduction
System and Kernel Level Security
User Security Features
Android Application Security
Recent Security Problems
Demo
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18. Device protection
• Screen lock
•Face unlock, Pattern, PIN, Passcode, …
• File Encryption
• 128AES with CBC and ESSIV:SHA256
• Master key encrypted with 128 bit AES via openssl library
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19. Passwords are hashed
•Salt saved on device
•/data/data/com.android.providers.settings.databases
•/data/system/locksettings.db
•‘Easily’ brute forced with salt
•Keys are stored in software!
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20. Android source code
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21. ANDROID
APPLICATION
SECURITY
Introduction
System and Kernel Level Security
User Security Features
Android Application Security
Recent Security Problems
Demo
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22. Android Permissions
• Accessing protected APIs
•Location (GPS), Camera, Bluetooth,Telephony,
SMS/MMS, Network/data
• Defined in AndroidManifest.xml
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23. Play Store security
• App is self signed
• Bouncer
•Online version
•Local version (since Android 4.2)
• App encryption
•Introduced in Android 4.1
•Shutdown due to bugs
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24. Cryptographic APIs
• Primitives
•AES, DSA, RSA, SHA
• Higher level
•SSL, HTTPS
• Virtual Private Network
•IPsec
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25. RECENT SECURITY
PROBLEMS
Introduction
System and Kernel Level Security
User Security Features
Android Application Security
Recent Security Problems
Demo
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26. SMS problems
• Smishing
•http://www.youtube.com/watch?v=baWeMbGatfs
• SMS to premium services
•F-secure MobileThreat Report Q4 2012
•Kaspersky Security Bulletin 2012
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27. Exynos Exploit
• Exynos 4210 and 4412 processor
•Sprint Galaxy S II, Galaxy S II, Galaxy S3, Galaxy Note, Galaxy
Note 2, GalaxyTab 2, Galaxy Note 10.1, Galaxy Camera
•Kernel: /dev/exynos-mem
 R/W by all users  access to all physical memory
• ExynosAbuse.apk
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28. DEMO
Introduction
System and Kernel Level Security
User Security Features
Android Application Security
Recent Security Problems
Demo
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29. References (I)
• F-secure MobileThreat Report Q4 2012, http://www.f-
secure.com/static/doc/labs_global/Research/Mobile%20Thre
at%20Report%20Q4%202012.pdf
• Google, “Android PlatformVersions.”,
http://developer.android.com/about/dashboards/index.html
#Platform
• Google, “Android Security Overview”,
http://source.android.com/tech/security/#android-
application-security
• S. Fahl, M. Harbach,T. Muders, M. Smith, L. Baumgärtner,
and B. Freisleben, “Why eve and mallory love android,” in
Proceedings of the 2012 ACM conference on Computer and
communications security - CCS ’12, (NewYork, NewYork,
USA), p. 50, ACM Press, 2012.
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30. References (II)
• J.-H. Hoepman and B. Jacobs, “Increased security through
open source”, Communications of the ACM, vol. 50, pp. 79–
83, Jan. 2007.
• Matthias Lange, “State of the Union: Android security
overview – Is Android the new XP?,
http://de.droidcon.com/2013/sessnio/state-union-android-
security-overview-android-new-xp
• Xuxian Jiang, “SmishingVulnerability in Multiple Android
Platforms”,
http://www.cs.ncsu.edu/faculty/jiang/smishing.html
• A. Shabtai, “Google Android: A Comprehensive Security
Assessment”, Security & Privacy, IEEE, vol. 8, pp. 35-44,
March-April 2010
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31. References (III)
• A. Barresi and P. Somogyvari, “Android Security – An
Introduction”,
www.youtube.com/watch?v=OOFzu2J3EBY
•Kaspersky Security Bulletin 2012,
https://www.securelist.com/en/analysis/204792255/Kas
persky_Security_Bulletin_2012_The_overall_statistics_f
or_2012
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32. http://2.bp.blogspot.com/-gZjNR3XVULs/T_ZOVgE-5lI/AAAAAAAAAg8/6YVmd5Q064o/s1600/questions11.jpg
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