SANS Digital Forensics and Incident Response Blog: Author - Dave Hull

Digital Forensics: Detecting time stamp manipulation

At approximately 22:50 CDT on 20101029 I responded to an event involving a user who had received an email from a friend with a link to some kid's games. The user said he tried to play the games, but that nothing happened. A few minutes later, the user saw a strange pop up message asking to send an error report about regwin.exe to Microsoft.

I opened a command prompt on the system, ran netstat and saw an established connection to a host on a different network on port 443. The process id belonged to a process named kids_games.exe.

I grabbed a copy of Mandiant's Memoryze and collected a memory image from the system and copied it to my laptop for offline analysis using Audit Viewer.

Audit Viewer gave the kids_games.exe process a very high Malware Rating Index (see Figure 1), so I decided there was probably more

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Digital Forensics: Persistence Registry keys

Some have called us log monkeys and claim our work is boring. Others recognize that what we do is a form of hunting. Computer Incident Response Team members watch security information event monitors (SIEMs) for indicators of compromise (IOCs). IOCs are like lycanthropes, they may be IDS/IPS alerts or blocks, or a system trying to connect to a resource it shouldn't be connecting to, or a user complaining of odd system behavior, or heaven forbid, a call from the Feds in the middle of the night.

Incident handlers may look for secondary IOCs to confirm an incident has occurred so they don't unnecessarily cause alarm or disrupt the organization. In the case of unsophisticated malware these secondary indicators can often be found by taking a quick look at the Windows Registry's run key. In many environments, this can be done remotely via:

reg query \\\\suspect.system.ip.address\\HKLM\\Software\\Microsoft\\Windows\\CurrentVersion\\Run

What comes back

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Digital Forensics Case Leads: Make it go away, the Stuxnet extended remix

Life is busy in the digital forensics and incident response world, so this week's Case Leads is short and sweet. Here are my favorite items from the last few days, enjoy!

If you have an interesting item you think should be included in the Digital Forensics Case Leads posts, you can send it to caseleads@sans.org.

Tools:

  • Harris Corporation introduces BlackJack a USB device that looks very useful for situations where one must rapidly triage systems for the presence of interesting data. According to the press release, the device boots in less than three seconds and "automatically scans and copies data by prioritizing search criteria and securely partitions search results for analysis." The device has two LEDs, one red and one green that indicate the presence or absence of items of interest.

Good Reads:


Computer Forensics: Identifying Disk Differences — Broken Mirrors

One Friday afternoon I was greeted by a large package from FedEx. Inside the giant box was supposed to be a hard disk drive on which I was to conduct digital forensic analysis. Opening the box and removing a few handfuls of packing peanuts revealed a bubble-wrapped Dell Tower. Obviously, the clients, like most non-computer folks, didn't know they could remove the actual hard disk drive from the tower and send those my way.

After grabbing the paperwork for this job, filling out my own chain-of-custody documentation and evidence receipt, I cracked open the tower and saw the following inside:

Image 1: Double SATA, double fun



Digital Forensics Case Leads: SQLite changes may impact your processes

I don't know if it's the time of year, the heat or what, but there's been so much going on over the last couple weeks that this post almost didn't make it out. Gasp! Thanks to the efforts of Ira Victor and Mark McKinnon (yay crowd-sourcing), we pulled it off. Speaking of crowd-sourcing, this post is meant to be a weekly round-up of things we've found that may be of interest to digital forensics and incident response practitioners, as such, please drop us a line at caseleads@sans.org if you have an item that you feel should be included in the weekly post. We appreciate it.

Tools:

  • Paraben's P2 Explorer is a great little free tool that mounts a variety of popular disk image formats, allowing the investigator to easily run a variety of tools against the mounted file system (e.g. anti-virus/malware scans).
  • Digital

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