The document discusses Android security, covering topics such as system and kernel level security, user security features, and application security. It highlights vulnerabilities like malware threats, recent security breaches, and the role of permissions in app security. The presentation emphasizes the importance of securing users' sensitive data and improving security features in Android operating systems.

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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