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

Quick Look - Cellebrite UFED Using Extract Phone Data & File System Dump

It is not the intent of this blog post to be an all-encompassing guide to the forensic analysis of an iPhone. Rather it is a look at some of the tools I use in my practice and how they can be applied to iPhone forensic analysis. That being said lets get to it.

Why would you use the Cellebrite File System Dump instead of the traditional Extract Phone Data ?

If the subject of your forensic analysis is collecting information regarding the telephone such as call logs, phone book, SMS, pictures, video and audio/music then you will find what you need using the standard Cellebrite processing found under "Extract Phone Data". However if you want to do a deep dive in to the file structure, Internet usage or look deep in to the applications that are being used on the device and perhaps run some of your "favorite forensic tools" against it, I highly recommend complimenting your traditional

...


Dealing with Split Raw Images in Digital Forensics

Hal Pomeranz, Deer Run Associates

Lately I've been working with images from a client whose policy is to create their dd type images as a series of 2GB chunks- the so-called split raw format. While commercial forensic tools will typically handle this format easily, split raw images can present challenges for examiners using Open Source utilities and Linux command-line tools. With image sizes constantly increasing, recombining the individual chunks of a split raw image into a single, monolithic image file is not really practical either in terms of analyst time or disk space. Happily, there are some Open Source utilities that can make dealing with split raw images considerably easier.

The Sleuth Kit

The Sleuth Kit utilities have actually supported split raw format since v2. The trick is to use the "-i split" option

...


Digital Forensics: Too Much Porn, Too Little Time

I recently had a case where one of the requirements was to determine if the PC had been used to view and or download pornographic images from the Internet. First let me say that in my view the only party that can ultimately determine if an image is pornographic is the court. That being said we agreed in the onset of the investigation that any image that clearly showed sexual organs would be the definition we would use in determining if a particular image met the client's definition of a pornographic image.

Processing the case with FTK 3.12 and both collecting images in allocated space as well as carving for images in unallocated space revealed well over 60,000 images. The client needed and answer quickly hence manually reviewing and classifying the large number of images was not an option. If you simply did a quick view of each image for just 5 seconds you would burn about 2 weeks of labor. The process needed to be automated and sooner than later. I had heard AccessData had

... Continue reading Digital Forensics: Too Much Porn, Too Little Time


Computer Forensics: Armor For Your Feet

Hal Pomeranz, Deer Run Associates

As forensic professionals we take a great deal of care when acquiring and analyzing evidence. Write blockers, checksumming, working copies- these are part of everybody's standard policies and help to prevent corruption of our digital evidence. However, beyond spoiling your original evidence, there are still various mistakes that you can make that won't ruin your case but will cost you time and increase your frustration level. In this article I'm going to demo a couple of different ways you can shoot yourself in the foot when doing forensics on the Unix command-line (e.g., in the SIFT workstation) and some easy ways to prevent these mistakes.

Output Redirection is Your Friend... Until It Isn't

Let's say you

...


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

...