When a user views a JPEG or PNG from Facebook (from a profile, album, etc.) the URLs tend to have "fbcdn" or "facebook" in the hostname. Profile pictures tend to contain "profile" in the hostname as well. To that subset of URLs you can apply all of these regular expressions to capture the user ID who owned that particular image. The a, s, n, and q characters in the URL refer to the size of the image. There are a few main varieties of image URLs, and these three expressions should help you parse them.
- /\d+(\d+)\d+_[qs]\. q is small, s is large
- [as](\d+)\d+\d+\. s is small, a is large
- \d+\d+(\d+)\d+\d+_[asnq]\. ''s is small, a is medium, n is large, q is square'
- "Facebook Forensics", SANS Computer Forensics and Incident Response Blog Entry, June 11, 2009. A few musings and links (that are reported above). Mostly with tracking photos to facebook.
- "Facebook Memory Forensics", SANS Computer Forensics Incident Response Log, Nov. 20, 2009. Discussion about facebook details left in memory.
- "Facebook Forensics", Valkyrie-X Security Research Group, July 5, 2011. Notes the groups successes and failures in recovering Facebook artifacts from RAM and storage.
- Netresec, January 30, 2011, thoughts about the impact of Facebook's SSL decision on network forensics.
- Facebook Forensic Toolkit eDiscovery toolkit to identify and clone full profiles; including wall posts, private messages, uploaded photos/tags, group details, graphically illustrate friend links, and generate expert reports.
- Belkasoft Evidence Center allows for carving Facebook data such as chats, wall posts and photos from Live RAM dumps, hibernation and pagefiles.
- Belkasoft Facebook Profile Saver is a free utility to download Facebook wall posts and photoalbums to a local computer.
- WebPreserver captures Facebook wall posts and about information as well as metadata in a legally authenticated manner.