Thursday, May 29, 2014

Bluetooth for data exfiltration. Say what?!? Part 4: Some Registry artifacts


Hello again readers and welcome back to another post regarding evidence left behind during Bluetooth data "exfiltration". Today's post is going to focus primarily on Registry artifacts. 

First of all, I want to point out a post made by Russ Taylor regarding Last Modified time updates. The "Last Modified" time stamps on Windows system files are no longer updated like they "used" to be and it is entirely possible to have time stamps from Registry hives and Event Logs (among other files) that are in the past, but the files themselves will have entries from the "future" For example, my NTUSER.dat timestamp was 05/19/2014 at 14:45:17, but the hive had entries from 05/20/2014 15:20:55. Great Scott! <cue Back to the Future music>

NTUSER.dat timestamp shows the "Last Modified" time 05/19/2014 14:45:17

Software-Atheros-VistaAddOn-Devices NTUSER.dat key updated at 05/20/2014 15:20:55. Great Scott!

The issue of "normal" time stamp updating seems to have been first noticed with Windows 7 and  underscores the fact that a forensicator cannot simply rely on file system time stamps alone. In fact, with a couple of lines in PowerShell, you can change timestamps with ease: 

$file = (gi malware.exe);
$file.CreationTime = '8/1/14 12:00AM';
$file.LastWriteTime = '8/1/14 12:00AM';

(Props to Brian Baskin for these exact commands. You may see these again some day....)



(NOTE: I want to test the time stamps out using a program like Triforce to see what additional data it can provide. It is on my list of things to do!)


So, now that we have covered the time stamps next up is covering some of the interesting data contained within the Registry itself.

The first example is in the aforementioned NTUSER.dat hive associated with my user account (which is cleverly named "Brian"). There is quite a bit of data located under the "Software-Atheros-VistaAddOn-Devices" path that looks to be associated with the connection of my Galaxy Note 2 via Bluetooth. I have to dig into the data more (when time permits) to try to figure out exactly "what" information can be determined from the Registry entry(ies). It still doesn't look like there is any evidence of actual "exfiltration" but it is nice to have another item that seems to match pretty closely to the connected device times. 

The Software-Atheros-VistaAddOn-Devices key screenshot, again!

X-Ways Forensics (my forensic analysis tool of choice) also has the ability to carve entries from Registry Hives. This also needs some more digging, as it looks like it is an entry regarding the command and the arguments needed to initiate the Bluetooth connection.



"Path unknown" Registry entry, with Win7UI.exe and the SCH-I605 Bluetooth MAC address

The SOFTWARE hive also had some entries associated with the Bluetooth connection under the path "Microsoft-Device Association Framework-Store" path. This also requires some more investigation, but once again, it does not appear that this shows anything along the lines of exfiltration, but only connections. These timestamps are prior to the timestamps entries that were created in the NTUSER.dat hive.

SOFTWARE entries regarding the Bluetooth connection


So at least we have a little more data that helps correlate some of the connection times, but we still have not found anything definitive that proves "exfil.doc" was indeed transferred from my computer to my phone via Bluetooth. But, the search continues...



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