Android– forensics and security testing

Santhosh Kumar

ANDROID – FORENSICS AND
SECURITY ANALYSIS

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.

Agenda:
 Introduction to android and its History.
 Study the Android File systems and
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Directories.
Bypass Passcodes (All types of locks).
Physical and Logical data extraction
techniquies.
Reverse engineer Android application.
Indian cyber Laws.

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.

Introduction to Android.History ??

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

Android Features.
 Android has key features which are useful as the
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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.

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)

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.

AOSP importance
 As Said Earlier AOSP maintains the
development and releases new versions and
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



fixes.
Compiling the AOSP is the best way to
understand the working of the Android.
http://source.android.com/source/initializing.h
tml
Not necessary for the Forensics analysts but
useful for the Deep Experimentation.
We don’t be Doing that now 

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.

LINUX commands:
Android Forensics involves
some of the Linux knowledge

following commands are useful



man

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help

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cd

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mkdir

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mount

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rmdir/rm –rf

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nano

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ls

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tree

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cat
dd
find
chown
chmod

sudo
apt-get
grep
| and >

Many more …………..

Environment Setup
 Ubuntu 32/64 bit ( I recommend 64 bit) with Android SDK

Ubuntu 12.04 (precise) 64 bit running on vmware/virtual
box
 http://www.vmware.com or http://www.virtualbox.org
 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.
 http://www.santoku-linux.com which is indeed made by

http://www.viaforensics.com a Mobile Pentesting
company.

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”

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)
cybertecturemirror.com



a 800+ android devices

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

ROM booting process



http://www.androidenea.com/20
09/06/android-boot-processfrom-power-on.html

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).

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.

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

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…..

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.

SD card info
 Most of the SDCARD details are stored in /data/
 App details in /data/data(it differs :P)

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)

ADB components
 Adbd on the devices.
 Adbd on the workstation.
 Adb on the workstation.

 Adb is free,primary tool for forensics and ofcourse opensource



Adb shell example
 Adb shell gives out lot of information(depends on root or not).
 The Data folder is useful when you are rooted.

Data from adb
 Sms History (Deleted).
 Contacts(com.phone.android)

 Call history
received,deleted,missed etc.
 Databook

 Events.
 Calender.

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

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)

Data Storage methods
 The main methods where sensitive data
stored.

 Shared preferences
 Internal storage
 External storage

 Sqlite3
 Network

Shared preferences
 It is where all the data which is shared between the apps are

stored.
 Key values are stored in XML files



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

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.

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.

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.

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

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.

Network & linux kernel
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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

Logcat
 Displays almost eveything that’s been going around your device

in the adb shell
http://developer.android.com/tools/help/logcat.html
 Has different parameters.

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?)

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 xda-developers.com

 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

Enable usb debugging when locked ?? Possible

Enable usb debugging when locked ?? Possible
BST(best smart tools)

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.

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 …………

Smudge attack
 Screen(digitalizer) is reflective

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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.

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.

Pattern Lock crack
 Key can also be decrypted ! Some sites do give

services for free.

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/com.android.providers.settings/databases/settin
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

Pwn face & voice unlock 
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

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 

Android Encryption
 Encrypts the entire device with AES encryption.
 Denoted to reduce in performance.
 Takes at Least a Hour for Encryption of Data.

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.

Android– forensics and security testing

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.

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.

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.

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

Permanent root
 not good as far as forensic is concerned.
 Leaves a huge footprint altering the evidence. Search xda for

more roots.

R00t with binary
 Gives root to almost all the 4.0 to 4.1

devices.

Kingo android root
 This one gives root over all

4.2.x,4.3.x,4.4.x

Android forensic techniques
 Logical and physical acquisition.
 Open source tools and some commerical

tools.
qtADB
Andriller
cellebrite
paraben
viaextract ….

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

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.

AFlogical
 Data Extraction tools.
 Free for law enforcement agencies.

 Records call logs,contact etc.

 DEMO

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$

Andriller
 A alternative and a powerful open source

tool.
 http://android.saz.lt/
 Made by Denis Sazonov @den4uk
 Give it a try you wont regret it
 DEMO…………………..

Photos
 Try looking here for more evidence.

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

Android/Torec.A
 First every Android based Tor malware

which was found in the wild.
 REVERSING DEMO

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.

Then there is ?
 Ill just leave this here :P

Wait ! Wait ? Wait ?
 SeAndroid was already defeated.The CVE 2013-6282
 Pau Olivia Had a POC based a toshiba tablet running 4.3 JB.



INDIAN cyberlaws
 Device as target or weapon
 IT act 2000

 IT amendment ACT (2008)
 Rules under 66A,43A,79
 SECTION 65A

http://www.cyberforensics.in/
http://deity.gov.in/content/cyber-laws

Recommended starters

Andrew Hoog

Steve robinson

Feedback welcomed :D

 Twitter:

https://twitter.com/security_
b0x
 securitypentrator@live.com

References:
 viaforensics.com
 Forensicfocus.com

 cellebrite.com
 android.saz.lt
 exploit-db.com

 www.forensicswiki.org/wiki/Cell_Phone_
Forensics
 Xda-developers.com

Android– forensics and security testing

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