Tuesday, January 11, 2011

What are you missing?

Hola Readers,
Every image is a special snowflake in regards to what software you find installed. There are times though when an investigator, myself included, gets comfortable as to what to expect and what they believe their tools are already doing for them. I had such an occasion last month when I found an image where the user was using Google Chrome as their browser. The case this was for is now settled and there was no public disclosure of my involvement in any form of declaration/affidavit/report so I will not be identifying the parties.

I was the second person to review the image at the time and we were looking to recover communications between our suspect and other parties around the time of his departure from his then current employer. What was suspiciously absent in our first round of reviews was a lack of web activity being reported from our standard tools. When this happens three things come to my mind for sanity checking:

1. When did the user profile I am looking at get created?
If this is a new system and I got handed it a couple days after the suspect started using it maybe what I'm seeing is correct. In this case, no the system had been in use for at least a year.

2. Is there any indications of popular 'cleaning' or wiping software being used?
Running through the user assist records, lnk files to no longer existent sources or other artifact sources that no longer show data after a consistent date are all signs of this. I will write another blog post about detecting what/when something was cleaned. In this case everything else was in place as it should be.

3. What other programs are installed? Am I missing something?
A quick look through the program files folder and user assist should be done at this point, is there something being used here that you hadn't dealt with previously. The user in this case had IE and firefox installed on his system so I didn't think to check for yet another web browser.


So I took a look through the keyword hits coming from his personal email address and noticed for the first time that they were contained within Chrome SQL Lite databases. Prior to this point I had not extracted the history files for a Chrome user and began a round of google searches to determine how to proceed.

While Google Chrome does make use of SQL Lite databases, basically flat files that contain a database structure that can be used like a relational database without the overhead, I didn't want to manual string together queries. I found two pages that helped me reach the evidence I needed.

The first located on the SANS blog provided me the information I needed regarding the structure of where the files should exist and what files I was most interested in. If I was looking to use log2timeline I could have stopped there, but I already have a license of NetAnalysis so I went to their site next.

Luckily for me in version 1.52 was announced in my inbox on 12/11/10 and now included Google Chrome support. So utilizing the information from the SANS blog I exported it to NetAnalysis for parsing and came up with all of the webmail usage I was expecting.

So the next time you don't find what you are expecting try my three steps and see if there is something you are missing.

If you know of a tool that supports Google Chrome histories besides log2timeline and NetAnalysis please comment or email with it.