A while back I assisted the FBI in the collection of evidence of a now convicted sexual offender. The guy had a hard drive full of child porn. My customer had suspicions that an employee in a remote office was accessing inappropriate material on their work computer and asked that I investigate it remotely. After finding one photo of a very young girl among a collection of "normal" porn and discussing it with my customer, I immediately dial my contact with the FBI. (Good contacts are ESSENTIAL don't wait until you need them to try and make them.) Although the young girl was clothed in the picture I saw, the lingerie and pose she was in was very disturbing and you just knew you didn't want to see anything else. At that point I froze; anything else that was touched remotely was altering and potentially destroying evidence on the remote drive. Within an hour the FBI was at the office. He used my machine and the access I had gained to briefly verify the contents of the drive and confirm that it required additional investigation. It did and they dispatched local agents to grab the drive for proper forensic collection.
I spared myself the imagery and let the FBI do what it needed to do using my machine. To me, this story is very interesting. Here a person in a very similar role as the one I played. He could be prosecuted for any residual images left behind on his drive after an investigation.
As far as I know, no CP was ever copied to my hard drive. I had donated a thumbdrive to the cause where all the evidence they needed during that brief investigation was collected. If it is a project I am working on with sensitive data (such as a penetration test) I like to keep everything in TrueCrypt volume making clean up very easy. But in this case, I wasn't driving. It was a windows box and I periodically run "CIPHER /W:C:\" to clean up all the residual files in the free space on the drive, but it’s not something I do religiously. How about you? Well, Cipher is running NOW!
Welcome to In Depth Defense. In Depth Defense LLC is a privately owned Information Security Consulting company owned and operated by Mark Baggett. In Depth Defense specializes in Penetration Testing and Incident Response. At this time In Depth Defense is not accepting any new client work, but we are happy to speak to you and point you to other resources in the community.
Mark Baggett has been active in Information Security for 18+ years. I've served in a variety of roles from software developer to CISO. You can find archives of older blog entries below and read my newer posts on http://www.pauldotcom.com, http://isc.sans.edu and http://pen-testing.sans.org