SANS Digital Forensics and Incident Response Blog: Category - Computer Forensics

OpenSaveMRU and LastVisitedMRU

Talking with a colleague the other day reminded me of just how nuanced many of the forensic artifacts are that we rely upon. Nowhere is this more true than in the Windows Registry. With no specification and even Microsoft products not following any data storage methodology, it is about as haphazard and irregular as they come. As an example, let's look at the OpenRunSaveMRU and LastVisitedMRU Registry keys. Both have been documented for years and are frequently cited in examinations. That being said, I would bet many examiners have not investigated the keys deeply enough to understand everything they are telling us. Here is a quick rundown on what we can glean from these keys.

OpenRunSaveMRU

In simplest terms, this key tracks files that have been opened or saved within a Windows shell dialog box. This happens to be a big data set, not only including web browsers like Internet Explorer and

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Digital Forensics Case Leads: New Gear, New PDFs Abuse, and Defeating TrueCrypt

Logicube releases new forensics gear, Didier Stevens discovers a new way to do interesting things with a PDF and a cooperative user, and Passware provides a means to defeat TrueCrypt.

Logicube has released two devices which look interesting. The MPFS or Massive Portable Forensic Storage provides up to 8TB of storage capacity for acquiring multiple images. The device may be attached to a forensic analyst's workstation via firewire, USB, or eSATA. The unit is compatible with Logicube's Dossier imager and Logicube's second new device, the NETConnect which as the name suggests, allows network access to forensic images. Based on the description, NETConnect is essentially a file server which enables multiple investigators to access forensic images as soon as they are acquired. The device supports Windows, Mac, and Linux and includes support for CIFS and NFS. (I've not had the opportunity to test either device but if Logicube or anyone else wants to send me a set, I will be

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Custodians of Digital Evidence

Let's think like a system administrator for a moment....

Here is the scenario:

You're the corporate incident handler/digital forensics person and you've just finished your latest case. The finished forensics report has been handed off to your boss, human resources, and the legal team. You are looking at your raid 5 volume with all of the data the case generated. With 500 gigabyte drives and terabyte drives almost a standard now, the case data might be nearly that big. So you back up your data and tools you used on the case to your DLT tape drive or another hard drive, wipe your drives, and pack the media away for storage.

Now it is four and half years later, legal counsel calls you into their office to tell you that the ex-employee has decided the sue. Not a problem, you've got your all of the case data backed up. It is just a matter of restoring it and providing copies to counsel as required.

But here is the problem, the DLT drive you have been using,

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Digital Forensic Sampling

Robert-Jan Mora and Bas Kloet have released an interesting paper called DigitalForensicSampling.pdf and it's about applying statistical sampling to digital forensics. Digital forensic practitioners are frequently faced with extremely large amounts of data to analyze, a situation that looks to get worse as storage capacities continue to increase. Mora and Kloet propose the use of random sampling for certain types of cases as a means of alleviating this problem.

Here's a quote from the paper's introduction:

In this paper we would like to address a few problems that we encounter in the digital forensic field,in general, which probably will get worse if our methods do not get smarter soon. A few problemsthat the digital forensic community has to deal with are:

  • The amount of data that needs to be investigated in cases increases every year;

The Chain of Custody for 2010-03-28 - Weekly Tweets