[Vol-users] LiME in real world Android forensics

masdif masdif at posteo.net
Fri May 30 05:55:38 CDT 2014


Thank you both, Andrew and Joe!

My fault: of course it sometimes is possible to get root access without 
rebooting. So my initial question is answered: Yes, you can use LiME 
with an initially un-rooted device.

--- tl;dr ---
But this is not always the case, is it? Is it imaginable to somehow 
quantify how often we can overcome the challenges of rooting, get kernel 
source, unlock screen, …?

Is it a waltz in general for average law enforcement forensics section?

Or do they have an address book of specialists for each 
device/ROM/version combination?

--- full length ---
I’m writing about Android volatile memory dump forensics. Even if this 
will be a thesis for a scientific degree, my goal is to include work on 
real world stuff. So the use case Joe asked for is that an examiner gets 
a running Android device with locked screen and is asked to forensically 
acquire the volatile memory ASAP. That is without changing the memory 
too much; neither by him nor by keeping the device in a safe for a few 
weeks while finding out how to handle his mission. At least I want to 
try to quantify stochastically how often this is possible and how often 
this is an unfeasible task respectively.

To my mind there are quite a few factors making examiner's live hard:

a) The device’s manufacturer and model should be determinable from the 
device’s body. Ok, easy in general if the device is not too exotic.

b) Next to find out is the operating system and version. You can guess 
that the manufacturer’s up-to-date standard ROM is on the device and no 
e. g. CyanogenMod or any other custom ROM. But how can you be sure?

c-a) For device and guessed ROM the examiner finds an exploit to root 
without reboot. How likely is that?

c-b) The rooting solutions I found up to now require interaction via 
touch screen. But in our case the screen is locked.

c-c) How about rooting really new devices like an “OnePluse One”? On 
the other side I myself got a low-cost retro “HTC Magic” to play with; 
and all sources I found on the internet about exploiting/rooting end in 
dead links or do not work anymore (Androot, Framaroot).

d) For device and guessed ROM the examiner finds the kernel sources to 
compile the LiME module against. This should not be a problem due to the 
open source license if we do not have to deal with a very exotic device.

e) How to switch on debugging with the screen locked?


In papers I found so far these questions were not really examined but 
circumvented by just using prepared devices. Examples:

Thing et al. [1] just mention: “The mobile phone used in our 
investigation was an Android mobile phone, the Google development set”. 
No further modifications are discussed.

Sylve [2] mentions “[…] an investigator should only use rooting 
techniques that have been verified to work reliably on a particular 
device and furthermore, verified not to have undesirable consequences, 
such as introduction of malicious code. The chosen rooting technique 
should also not require the device to be reset, which will likely wipe 
volatile memory.” But the paper’s focus is not on “rooting toolkit 
quality management”. This aspect Sylve skipped in [3].

Ali-Gombe [4] gets root access without rebooting on two Motorola 
devices with Androot. (But “Universal Androot v1.6.1” did not work for 
my own retro “HTC Magic”.)

Macht [5] writes: “What method works depends heavily on the device and 
the Android version it is powered by. […] Because of this, this thesis 
assumes that an unlocked, rooted device is already available […]”

Xenakis et al. [6] work with DDMS on emulator and phones without 
mentioning how they were prepared. Later in [7] they described using 
LiME but mentioned some of the limitations I see: “1. It requires rooted 
devices […] 2. […] The source code of kernel is not always available 
[…]3. It requires the config.gz file […].”



[1] Thing et al. (2010-08) - Live memory forensics of mobile phones
     http://dfrws.org/2010/proceedings/2010-309.pdf
[2] Sylve (2011-12) - Android Memory Capture and Applications for 
Security and Privacy
     
http://scholarworks.uno.edu/cgi/viewcontent.cgi?article=2348&context=td
[3] Sylve (2012-02) - Acquisition and analysis of volatile memory from 
android devices
     
http://www.504ensics.com/uploads/publications/android-memory-analysis-DI.pdf
[4] Ali-Gombe (2012-01) - Volatile Memory Message Carving - A per 
process basis Approach
     
http://scholarworks.uno.edu/cgi/viewcontent.cgi?article=2614&context=td
[5] Macht (2013-01) - Live Memory Forensics on Android with Volatility
     
https://www1.informatik.uni-erlangen.de/filepool/publications/Live_Memory_Forensics_on_Android_with_Volatility.pdf
[6] Xenakis et al. (2013-04) - Discovering Authentication Credentials 
in Volatile Memory of Android Mobile Devices
     
http://cgi.di.uoa.gr/~xenakis/Published/49-I3E-2013/2013-I3E-AMNX.pdf
[7] Xenakis et al. (2013-12) - Acquisition and Analysis of Android 
Memory
     
http://www.ucd.ie/cci/cync/Acquisition%20and%20Analysis%20of%20Android%20Memory.pdf



Thanks a lot and have a great weekend,
Philipp


________________________________________________________________
 From:    Joe Sylve
Sent:    Friday, May 30, 2014 3:41AM
To:      Andrew Case
Cc:      Vol-users, Masdif
Subject: Re: [Vol-users] LiME in real world Android forensics

> What andrew said us completely accurate.  What is your specific use 
> case
> (if I may ask)?
> On May 29, 2014 8:33 PM, "Andrew Case" <atcuno at gmail.com> wrote:
> 
>> If phone is rooted you can then just insmod the compiled LiME module
>> into it.
>> 
>> If the phone is not rooted then the best case is temporarily rooting 
>> the
>> phone (using an exploit that does not require a reboot), and then 
>> using
>> the temp root access to load the module.
>> 
>> Thanks,
>> Andrew (@attrc)
>> 
>> On 5/17/2014 8:10 AM, masdif wrote:
>>> Hi all,
>>> 
>>> Android Memory acquisition will be part of a paper I have to write. 
>>> So
>>> far I have no problem to follow the description for an AVD on
>>> https://code.google.com/p/volatility/wiki/AndroidMemoryForensic
>>> 
>>> Please excuse this noob question (and my bad English) but I'm going
>>> crazy figuring this out:
>>> 
>>> Can LiME be used in real life Android forensics that is Android 
>>> memory
>>> is acquired without having to reboot the Android device beforehand?
>>> 
>>> Let's say:
>>> I get an running Android mobile phone and for some lucky reason it 
>>> is
>>> both rooted and the user interface unlocked. (Are there any 
>>> statistics
>>> available how often this is the case?) My task is to acquire its 
>>> RAM.
>>> 
>>> As far as I understood in order to use Lime for RAM acquisition I 
>>> have to
>>> a) get the Android kernel's source code from the manufacturer,
>>> b) cross compile a new kernel with some settings for later being 
>>> able to
>>> insmod the LiME kernel module,
>>> c) flash the compiled kernel onto the phone and
>>> d) reboot the phone to get the new kernel running, which
>>> e) destroys all the RAM I wanted to acquire, before I can
>>> f) insmod LiME.
>>> 
>>> Please be patient and give me a hint where I'm going wrong?!
>>> 
>>> All papers I found so far used prepared phones.
>>> 
>>> 
>>> Thanks a lot and have a nice weekend,
>>> Philipp
>>> _______________________________________________
>>> Vol-users mailing list
>>> Vol-users at volatilityfoundation.org
>>> http://lists.volatilityfoundation.org/mailman/listinfo/vol-users
>>> 
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