SANS Digital Forensics and Incident Response Blog: Category - Timeline Analysis

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 Case Leads: Reverse Engineer Malware, Analyze Timelines and Report Findings

This week, we have a wealth of information about REMnux, Lenny Zeltser's Linux distribution for analyzing malware, Kristinn Gudjonsson's paper on Super Timeline Analysis, and some interesting report-writing posts that I wanted to recall attention to. There's a lot of interesting reading ahead, so without further ado...

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.

Reverse Engineering Malware:

Since he released his REMnux distribution for analyzing malware, our friend Lenny Zeltser has gotten quite a bit of attention for his distribution and for his SANS class, Reverse Engineering Malware.

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Benefits of using multiple timestamps during timeline analysis in digital forensics

Timeline analysis is a highly valuable tool. However, like everything else in computer forensics, it requires a skilled investigator to examine all the data available in order to find the evidence and provide an accurate account of the events. When analyzing Windows systems, it is common to use key timestamps in forensics such as Creation Date, Last Modified Date, Last Accessed Date, and the Last Modified Date for the file's Master File Table (MFT) entry. A key factor in using these timestamps is to not rely solely on a single timestamp, but use the combination of these timestamps in digital forensics. The combination of these timestamps can prove to be far more powerful and revealing than any single timestamp on its own. I will use an example to illustrate.

A forensic investigator was reviewing volatile evidence collected during an investigation into

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Stop, Children, What's That Sound?

Making Use of a Super Timeline

I won't go over how to create a Super Timeline since Rob has already covered that as a high level in on the SANS Digital Forensics Blog. What I've been working on recently is how to best make use of the resulting timeline. I have also discovered some interesting artifacts that never occurred to me to consider as part of a timeline.

What I've learned is that creating a Super Timeline is only the beginning of timeline analysis. Because the Super Timeline method captures so many time stamps, it islikely that a SuperTimeline will contain too many entries to manually review line by line especially if an examiner creates a timeline for an entire drive image.The challenge is to be able to pin down what portions of that timeline are relevant to the examination at hand.

What I recommend

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exFAT File System Time Zone Concerns

exFAT Time Zone Concerns

The exFAT file system tracks the time zone offset of all MAC time's stored for the respective file. The file system uses 32-bit time stamps (and another byte tracking 10ms increments). Additionally, all time stamps are recorded to the file system as local machine time while applying a time zone offset that is also stored when a file is changed/modified/accessed. The implications of this include being able to track removable media across several time zones without the need for the system they were used in. (For a more detailed look at the exFAT file system, see Robert Shullich's paper on SANS Computer Forensics Resources).

exFAT stores time zone offsets in a one byte value. Vista SP1 (the first desktop release of exFAT) did NOT utilize the time zone byte. In this case, the time zone bytes will be 0x00. Since the OS

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