Android– forensics and security testing


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Speaker:Santhosh Kumar
Event:Defcon Kerala
Android-Forensic and Security Analysis.
Android one of the leading Mobile Operating System which is managed by Google released back in 2008 now stands with a 4.4.x version Android KitKat.The Study Shows that increasing Crime Rates are switching from Computer Centered to PDA Based.Crime against Women,Children And Abuse.As the Digital Forensics and Law Enforcement Agencies find new Hard Challenges Cracking Down different Situation in the Android Environment.Google Play Store which has over 1 Million Application Active has also added to the Pain.
The Talk Focus on various Methods,the Various Situation where the forensics is useful.
The Methods are classified as Logical and physical which involves from breaking the passcodes to exploring virtual NAND memory.
The talk also focus on various places where is information is available to the forensic point of view.
Affected by Mobile Cyber Attack? Tortured by a Android Smartphone ? Relax there is a solution to each and everything.
The Talk also focus on using both Windows And linux as the Forensic Investigation Environment.
Android Which has the linux kernel at Heart can be best paradise when it comes to Forensic Data.
Various Tools on way this can be done in faster way.

Forensic always useful whether you are from a corporate environment or even from the massive Law enforcement Agencies.

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  • Android– forensics and security testing

    2. 2. r00t@b0x : whoami?  Security Researcher for a quite sometime  (certs:CEH)  POC at Defcon Chennai.  Currently Working on ARM based Exploitation.  Reported some Web apps at Microsoft , yahoo,intel,ibm,cisco etc.  Currently doing Bachelors in Computer Science.
    3. 3. Agenda:  Introduction to android and its History.  Study the Android File systems and     Directories. Bypass Passcodes (All types of locks). Physical and Logical data extraction techniquies. Reverse engineer Android application. Indian cyber Laws.
    4. 4. Why forensics ? WTH is this?  Evidence for legal proceedings.  Financial Crime.  Pornography/Child Pornography (pedophiles).  Sexual harrasment! (against women)  Terrorism activity or national threat.  Cyber threats.  Counter intelligence.  Murder or other crimes.  Eg:Georgia wieldman attacked @confidence conference Poland.
    5. 5. Introduction to Android.History ??
    6. 6. Introduction to Android!History?  Widely Used Smartphone OS with over 77% share in 2013.  The man behind Android was “andy rubin” orginally which now developed by google(2007)  Android now has over 900 million devices as per the IO event in 2013.  Android Open Source Project (AOSP) which was primarily based on the LINUX which is now responsible for the Development and Maintanence Commits and Releases.  AOSP Follows the GPL v2 license and the Apache V2.0 license.The GPL v2 makes it mandatory to keep the source code as open source.Apache 2.0 is used for commericial entities
    7. 7. Android Features.  Android has key features which are useful as the       forensic point of view. Features like GSM,CDMA,LTE,WiMax,Wifi,Bluttooth etc. Google Play Store/Android Market is Rich source for forensic Analysis. Data Storage. Flash(or nand) memory . Internal Memory. External Memory.
    8. 8. Android Overview:  Global System for Mobile Communications – GSM Subscriber Identity Module or Unique Subscriber Identity Module (SIM OR USIM) to identify the user for the celullar network. Eg:AT&,T-Mobile (US) India-BSNL,AIRTEL  Code Division Multiple Access – CDMA Eg:Sprit,version – US INDIA- Tata Docomo,MTS INDIA  Intergrated Digital Enhanced Network – IDEN which is yet to be avaible in india | US- Sprit.  WorldWide internop for microwave access – WiMax US-Sprit INDIA- BSNL,Reliance.  Long Term Evolution – LTS (4 G) US-AT&T,Sprit,T-MOBILE,Verizon INDIA- Airtel,Aircel(TD-LTE)
    9. 9. Android Overview:APPS
    10. 10. Android Overview:Apps  The Total Android Apps Crossed Over 1 Million in NOV 2013 with another 70000 Apps Published in JAN 2014.  The other competitor,Apple which has the Strict App Uploading and Review Process which can go through long amount of time,on Fullfilling many criteria and condtions.Sometimes the apps are denied over after long review. iOS doesn’t allow the apps which are away from the App Market.  Google,Which requires less process for submitting the app (such as the secure key) While google has the power to Remove the app from the market,Ban Hammer the Developer and Remotely uninstall the app.
    11. 11. AOSP importance  As Said Earlier AOSP maintains the development and releases new versions and     fixes. Compiling the AOSP is the best way to understand the working of the Android. tml Not necessary for the Forensics analysts but useful for the Deep Experimentation. We don’t be Doing that now 
    12. 12. Linux,Open source Software in Forensics  Open source forensic tools have always been more effective in the digital forensic discipline.Open source tools always has upper hand than closed source tools The Power to View the source code and understand the working of it. The ability to share software and improve it by working together with the forensic community. Free or Low Cost.  Linux is not only a critical component in Android but can be effectively used in forensic analysis.
    13. 13. LINUX commands: Android Forensics involves some of the Linux knowledge following commands are useful  man   help   cd  mkdir  mount  rmdir/rm –rf  nano   ls   tree      cat dd find chown chmod sudo apt-get grep | and > Many more …………..
    14. 14. Environment Setup  Ubuntu 32/64 bit ( I recommend 64 bit) with Android SDK Ubuntu 12.04 (precise) 64 bit running on vmware/virtual box  or  Have atleast 20 Gb free Space and 2 GB ram .  Have Windows for Some commercial tools (explained later)  I recommend Santoku Linux which is a entire hacking distro dedicated to Mobile forensics and Security.  which is indeed made by a Mobile Pentesting company.
    15. 15. Workstation Setup:Caution  Disable Automount (file systems)  Command:gconf-editor  It is because auto mounting of file system can screw our setup and alter the evidence .  Go to apps : nautilus>preferences > remove “media _automount” and “media_automount_open”
    16. 16. Android Architecture
    17. 17. HARDWARE DEVICES  Cameras  Smartphones  Gamming consoles  Tablets  DECT phones  Google Tv (a Android Landline)  Smart TV’s  Car Audio Systems  Google Glasses  Smart Watch  GPS  Fridge and Washing Machine (DAFAQ)  Mirrors (you Saw it right :P)  a 800+ android devices
    18. 18. ROM Booting process  Stock Rom varies from manufacturer to manufacturer  Acutally Phone booting process.  Short Seven ROM booting process  Power on and boot ROM code execution  The boot loader  The Linux kernel  The init process  Zygote and Dalvik  The system server  Boot completed
    19. 19. ROM booting process  09/06/android-boot-processfrom-power-on.html
    20. 20. Android Application Security Model  Android at the installation of the App(.apk) check for the developers unique signature. (Not CA).  Next it gives out the display of the android app file permission. The source is located in the androidmanifest.xml  This file is the potential when it comes to forensic analysis and determine the permission(malicious app).
    21. 21. Application process  Quick review of the android app execution.  Even though Android apps are made in java but they are not executed in java format.  Each app gets a unique linux ID(uid) and Groud ID(gid).  Gets own dedicated process and dedicated dalvik VM.  The App Data gets stored in Data /data/data/<app process>accessible only by UID and GID.(root exceptional).  Apps can share the data with other apps using content providers.
    22. 22. Some files which is useful  Cache.img :disk image of the /cache partion.  Sdcard.img:disk img of the cache partion(img here is from AVD emulator)  Userdata-emu.img: disk image of the data partion.  …. Useful in the areas of forensics
    23. 23. USB connection of the evidence device  Different Devices have different options.  The common four are Charge only file transfer  Sync Internet tethering.  Check the connection to the host by typing “dmesg”.  Make sure you take care not to alter the evidence much…..
    24. 24. Checking USB connection
    25. 25. Precautions : (must needed)  Make sure to Disable auto mount feature in ubuntu to prevent automatic detection and mounting of USB storage.  Every fragile change could lead to alteration of evidence.  Hardware write blocker useful to some extent.
    26. 26. SD card info  Most of the SDCARD details are stored in /data/  App details in /data/data(it differs :P)
    27. 27. Android Debug bridge
    28. 28. Android Debug Bridge  Most important component when it comes to android forensics.  Consider it as a swiss army knife for forensics and security analystis.  Enable usb debugging developer options > usb debugging.  This will run adbd (daemon) on the devices.  Adbd runs on the user account(UID) unless promted with the root privileges.  If your device is locked then it is difficult to unlock usb debugging.(not 100% impossible)
    29. 29. ADB components  Adbd on the devices.  Adbd on the workstation.  Adb on the workstation.  Adb is free,primary tool for forensics and ofcourse opensource 
    30. 30. Adb shell example  Adb shell gives out lot of information(depends on root or not).  The Data folder is useful when you are rooted.
    31. 31. Data from adb  Sms History (Deleted).  Contacts(  Call history received,deleted,missed etc.  Databook  Events.  Calender.
    32. 32. File Systems  Lot of file systems in the android operating system.  More than a dozen is in use.  The main three are EXT FAT32 YAFFs2 Source for the user data
    33. 33. Data to expect in /data/data  Apps that are shipped with stock rom : browsers.  Apps that are manufacturer specific : eg : HTC sense,touchwiz,motoblur  Wireless carrier apps (not common in india) : carrier IQ  Apps installed by google default : play store,play music , maps  Apps installed by user (both marketplace and unknown source installation)
    34. 34. Data Storage methods  The main methods where sensitive data stored.  Shared preferences  Internal storage  External storage  Sqlite3  Network
    35. 35. Shared preferences  It is where all the data which is shared between the apps are stored.  Key values are stored in XML files 
    36. 36. Internal Storage  Common in most of the systems :ext3,ext4,yaffs2  Unrooted user cannot access /data/data as it is encrypted.root is needed for viewing the contents
    37. 37. Internal storage  U0_a0 is the owner means it is that user who installed the app “truecaller”.  These apps and their directories are damn useful when it comes to finding evidence.
    38. 38. External Storage  It has less restrictions when compared to the internal storage.  FAT 32 is commonly found file system on the sdcard.  As suggested earlier most apps data is stored here it is better to look here.
    39. 39. SQLITE3-Native app database.  Lightweight RDBMS which has the c programming library.  Entire DB stored in single file.  Most of the App developers store the database in internal memory eg /data/data/<app name>/database.
    40. 40. SQLITE3-some useful commands  Sqlite3 <dbfilename>  Loads the db  .tables  Shows the tables  .headers on|off  Turns headers on/off  .mode  Output mode file type  Select * from <table>  Displays the table attirubutes  .dump?table?  Dump the table  .quit  Exit the shell prompt
    41. 41. Sqlite3 datbase example  Little catch : sqlite3 is not installed in real phones by default.  For test conditions I have used avd emulator from android.  Those databases have lot of tables which can be real handy.  Some native roots have sqlite3 symlinked by default.
    42. 42. Network & linux kernel     Network storage in java and android classes Not locally but on the on network and relative datbases. The least place we look at the heart:linux kernel | kernel logs. To access the kernel logs we have “dmesg” command on the adb shell  Source:andrew hoog
    43. 43. Logcat  Displays almost eveything that’s been going around your device in the adb shell  Has different parameters.
    44. 44. Device Handling & forensic rule  The main motto:Avoid modification to evidence at all costs.  Simple mounting of device could lead to altering of evidences.  Increase the sleep timeout which could lead to locking of the device.  Logcat everything what is going on.  Make sure minimal modification to the evidence.  Enable do not sleep while charging.  Put the device on the flightmode or remove the sim card(I don’t recommend this).  Never switch off the device if it is on unlocked or on locked.  Work where no network connnectivity (REMOTE WIPE & SMS malwares to rip evidences?)
    45. 45. Phone switched off? What to do?  Try to boot into the recovery~ most of the devices power+vol up +down or power + vol down and then up .  If you cant come up search  Connect to adb,check for the root permission  Usb debugg enabled you are lucky or else you have find a way to remote activate usb debugg
    46. 46. Enable usb debugging when locked ?? Possible
    47. 47. Enable usb debugging when locked ?? Possible BST(best smart tools)
    48. 48. Crack the codes 
    49. 49. Unlucky still? Here comes the passcodes breaking!  Very useful when it comes to forensic! Nothing beats this .  Various techniques for breaking android passcodes.  Few will be discussed here.  There is no direct rule for breaking passcodes.
    50. 50. Types of passwords ?
    51. 51. Types of passwords ?
    52. 52. Cracking techniques  Smudge attack.  Pattern lock vulnerability.  Psneuter with adb,usb debugg(if enabled).  Cracking the password key.  Face unlock pwn with a picture.  Continues to evolve …………
    53. 53. Smudge attack  Screen(digitalizer) is reflective     surface,smudge(pattern) which diffuse in the glass. Being dust particle,when exposed to light reflect them. camera setup to capture the overexposed image around 6-8 times will give a 80% correct image. It gives out the display pattern. Not always working,like playing temple run could remove the smudge totally.
    54. 54. Smudge attack
    55. 55. Pattern Lock crack  Pattern creates a file in /data/system/gesture.key  Hash is stored there.if custom recovery is installed like TWRP recovery,CWM recovery etc.  Remove the key using the rm command and recreate it using your own hash.
    56. 56. Pattern Lock crack  Key can also be decrypted ! Some sites do give services for free.
    57. 57. Cracking pins  When password/pins are used they are stored in /data/system/passwords.key  As you can see it is not in plaintext but as Random+sha1+md5.  Not easy depends on the nature of password.  Pull the salt from/data/data/ gs.db and get the password from above.  Put them in the folder and try to attack them in password recovery tools such as hashcat/john the ripper by bruteforcing them
    58. 58. Pwn face & voice unlock      Not secure at all when google introduced it in android 4.0. Reported to unlock with the photo of the person. After kitkat android update the face unlock when to a change where the person have to unlock by blinking the eye which shows the alive ness of the captured image. Again easily broken by duck faces,smiling images from facebook :P  “In June 2013, details emerged of a Google patent, pictured, that would let users unlock their phones by pulling silly faces, such as frowning, poking out their tongue or wriggling their nose. The expression would then be scanned and compared to a previously captured photo to confirm the user's identity”- dailymail(uk). Voice can easily spoofed by old school tricks 
    59. 59. Android Encryption  Encrypts the entire device with AES encryption.  Denoted to reduce in performance.  Takes at Least a Hour for Encryption of Data.
    60. 60. Get fRoSted  Frost Security Team was able to break the encryption by cooling the device to -15 c in 60 minutes.  Switch off and Flash the Frost Recovery.  Not the entire AES keys are decrypted.Some bits were decayed.
    61. 61. g0t r00t?
    62. 62. g0t root?  90% of forensics trick depends on the root?  Not enabled even in a single device.(unless suspect      rooted on his own). Not possible on all devices without altering the evidence. Gaining root will leave a lot of traces. Many data’s they get altered. Takes lot of time searching for the correct exploit sometimes lead to hard brick/soft brick. Root could make the device more vulnerable for future exploits.
    63. 63. Types of r00t?  Temp root: gives you root access till you reboot the device.  Recovery root: custom recovery such as clockworkmod(CWW),twrp etc will give root access in the recovery.  Permanent root:install su to the system leaving a huge footprint.most custom roms have perm root by default eg:cyanogenmod,omni,panodroid etc.
    64. 64. Temporary root  Temp root is something essential when it come to forensic.(z4root.apk)  Doesn’t work on all devices,test it first before using.
    65. 65. Psneturer a temp root solution.  Neturer is a android server.this app exploits that server giving us a temprarory solution.  adb devices  adb push psneuter /data/local/tmp  adb shell  cd /data/local/tmp  chmod 777 psneuter  ./psneuter
    66. 66. Permanent root  not good as far as forensic is concerned.  Leaves a huge footprint altering the evidence. Search xda for more roots.
    67. 67. R00t with binary  Gives root to almost all the 4.0 to 4.1 devices.
    68. 68. Kingo android root  This one gives root over all 4.2.x,4.3.x,4.4.x
    69. 69. Android forensic techniques  Logical and physical acquisition.  Open source tools and some commerical tools. qtADB Andriller cellebrite paraben viaextract ….
    70. 70. Logical vs physical Acquisition Logical physcial  Access to file systems  Exploring the  Data which is already memory,not the file system.  More data than logical,by breaking passwords etc available to user Eg:ADB pull,aflogical  Hardware and software
    71. 71. Logical Sdcard anquisition  Apps Data gets stored in /data which is encrypted     and root access. SD cards where the user stuffs stays.(audio,video,maps). Uses cross platform FAT FS. Most backup stored in Sdcard. .apk’s in sdcard might be encrypted.  Useful done when 3rd party apps are analysis.
    72. 72. ADB pull -logical
    73. 73. qtADB
    74. 74. AFlogical  Data Extraction tools.  Free for law enforcement agencies.  Records call logs,contact etc.  DEMO
    75. 75. UFED touch ultimate  UFED Touch Ultimate, enables the most technologically advanced extraction, decoding, analysis and reporting of mobile data. It performs physical, logical, file system and password extraction of all data (even if deleted) from the widest range of devices including legacy and feature phones, smartphones, portable GPS devices, tablets and phones manufactured with Chinese chipsets. Cost:10000$
    76. 76. UFED what’sapp analysis
    77. 77. Device Seizure
    78. 78. Device Seizure:Report
    79. 79. Andriller  A alternative and a powerful open source tool.   Made by Denis Sazonov @den4uk  Give it a try you wont regret it  DEMO…………………..
    80. 80. Photos  Try looking here for more evidence.
    81. 81. Reversing Apk’s  Rename Android app (.apk) to .zip.  Extract zip  Run dex2jar on the extracted file.  Open the .jar in a java decompiler.  APKTOOL  Androguard  Apkinspector
    82. 82. Android/Torec.A  First every Android based Tor malware which was found in the wild.  REVERSING DEMO
    83. 83. Future of Android forensics  The future research work will be on the Seandroid.  Contributed by National Security Agency (NSA) *cough*  Motto to have secure android.
    84. 84. Then there is ?  Ill just leave this here :P
    85. 85. Wait ! Wait ? Wait ?  SeAndroid was already defeated.The CVE 2013-6282  Pau Olivia Had a POC based a toshiba tablet running 4.3 JB. 
    86. 86. INDIAN cyberlaws  Device as target or weapon  IT act 2000  IT amendment ACT (2008)  Rules under 66A,43A,79  SECTION 65A
    87. 87. ANY QUESTIONS?
    88. 88. Recommended starters Andrew Hoog Steve robinson
    89. 89. Feedback welcomed :D  Twitter: b0x 
    90. 90. References:       Forensics 
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