The Android Security Jungle: Pitfalls, Threats & Survival Tips

Presented by Scott Alexander-Bown at GOTO Copenhagen 2015

Transcript

1. The Android security jungle: pitfalls, threats and survival tips Scott Alexander-Bown @scottyab
2. The Jungle • Ecosystem • Google’s protection • Threats • Risks
3. • Network • Data protection (encryption) • App/device integrity • App binary security • Testing Survival
4. • Lead Android Dev (remote) at Intohand • Co-Author - Android Security Cookbook • Co-Founder of SWmobile Scott Alexander-Bown
5. 1.4 Billion users
6. OpenSignals.com
8. Security Services • Google Play • Approval process (human approval since 2015) • Developer security notifications • Android Bouncer • Android device manager (Device security) • Safety net (intrusion detection) • Android at Work
9. Slide Adrian Ludwig’s - Android Security State of the Union
10. Newer version of Android are more secure 1.5 stack buffer, integer overflow protection 2.3+ null pointer dereference mitigation, NX 4.0+ ASLR 4.1+ ASLR strengthened 4.3 Security-Enhanced Linux 5.0 Security-Enhanced Linux - enforcing Updatabled Webview (via playstore)
11. Threats
12. Threats: App Hijacking • Taking an app and adding malware • Concerns • Reversing Android apps is easy • No need for certificate authority • Sideload
13. “I ain’t got time to (heart)bleed”
16. OWASP • Mobile Security Project • iOS and Android • Top 10 risks • attack vectors • threat agents • impacts
17. OWASP top 10 risks • M1: Weak Server Side Controls • M2: Insecure Data Storage • M3: Insufficient Transport Layer Protection • M4: Unintended Data Leakage • M5: Poor Authorization and Authentication • M6: Broken Cryptography • M7: Client Side Injection • M8: Security Decisions Via Untrusted Inputs • M9: Improper Session Handling • M10: Lack of Binary Protections
18. Survival kit
19. Survival tips 1. Harden the network communications 2. Protect stored data (encryption) 3. Validate the device and app integrity 4. Increase binary security
20. Network communications • Use SSL / TLS! • Use the platform SSL/TLS validation (i.e don’t disable it!) • Use only strong cipher suites (128bit+) and TLS versions (TLS v1.2) • OkHttp 2.1 - https://publicobject.com/2014/11/12/okhttp-2-1/
21. Looks like you’re not using SSL pinning? • Devices ship with 100+ Certificate Authorities (CA) and users can install their own • Pinning limits the trusted root CA’s • Two types • Certificate pinning • Public Key pinning
22. Public key pinning
23. Patch against SSL exploits • Google Play Services provides a dynamic security provider • ProviderInstaller.installIfNeeded(getContext()); • https://developer.android.com/training/articles/security-gms- provider.html#patching
24. Tips
25. Password based encryption Code in a slide :’(
26. Encryption libraries • Conceal • https://facebook.github.io/conceal • SQL cipher https://www.zetetic.net/sqlcipher/sqlcipher-for-android/ • Secure-Preferences (or Hawk) • https://github.com/scottyab/secure-preferences
27. Hardcoded encryption key
28. Verifying App integrity • Debuggable check • Apk Checksum • Signing certificate verification
29. Signing Certificate Verification Build-time Runtime 1. Get you certificate signature $keytool -list -v -keystore your_app.keystore 2. Embed in app String CERTIFICATE_SHA1 = “71920AC9486E087DCBCF5C7F6F…”; 3. Get the Signature from the PackageManager 4. Hash the Signature 5. Compare the signature hashes strings
30. Verifying device integrity • Emulator check • https://github.com/strazzere/a nti-emulator • Google SafteyNet test • https://github.com/scottyab/sa fetynethelper
31. root@android:/ # • Root apps / Dangerous apps • Suspect system properties • SU/BusyBox binaries • RW /system • https://github.com/scottyab/rootbeer
32. Obfuscation
33. ProGuard • Java code obfuscator • Part of the Android SDK • Free as in Beer! • ReTrace - Supported by Error handling services such as Crashlytics
34. DexGuard • Commercial version of ProGuard • Designed for Android and protection • Useful security utils - SSL Pinning, Root check, logging removal etc • My favourite features • String Encryption • API hiding
36. Quick Android Review Kit (Quak) • Python script • Works with .apk or source code • Automated tests • weaknesses • exploits • Creates exploit .apks • https://github.com/linkedin/qark
38. Click here for more! • 42+ Secure mobile development tips http://bit.ly/viafor42 • OWASP Mobile security risks http://bit.ly/owaspmobile • Android security cookbook [book] http://bit.ly/MscEFu • Android security internals [book] http://bit.ly/andsecint • Droidsec (whitepapers) droidsec.org/wiki
41. • @gotocph • @intohand • 20th Century Fox • Android security team Thanks
42. Questions? dev@scottyab.com @scottyab github.com/scottyab Please Remember to rate this session Thank you
45. WebView • Before • getSettings().setJavaScriptEnabled(false) • getSettings().setAllowFileAccess(false) • During • WebViewClient.shouldOverrideUrlLoading() • enforce local content or Https • Whitelisted hosts/urls • .shouldInterceptRequest() to intercept XmlHttpRequests • After • webview.clearCache(true)