Wednesday, November 25, 2009

More Timeline Creation Techniques

Some of you may have seen (or be using) the timeline tools I released within the Win4n6 Yahoo group and included in my most recent Hakin9 article on Windows Timeline Analysis. If you've taken a look at the tools, you'll notice that I have some tools available for parsing Event Logs from Windows 2000, XP, and 2003 (i.e., .evt files) into the timeline (TLN) format I use. However, there's nothing there, at the moment, for parsing Windows Event Log/.evtx files from Vista, Windows 2008, or Windows 7.

A quick look around showed me that there weren't many free (as in beer) tools for parsing .evtx files. Andreas Schuster has done a good deal of work in this area, has picked apart some of the .evtx data types, and made some tools and an article on the subject available. However, these tools are somewhat limited due to the nature of the new .evtx file format.

Then along came LogParser...freely available from MS and extremely flexible. There are a number of sites available that are dedicated to or include the use of LogParser, and there's even a GUI or two available. However, that's a bit beyond what we're going to talk about at the moment.

You can download the Logparser.msi file from MS and install it, and then copy the files from the installation folder to a thumb drive or CD, making the tool available for live incident response activities. What this means is that you now have a platform-independent means for extracting event records from Windows systems. Using this command:

E:\>logparser -i:evt -o:csv "Select * from System" > %ComputerName%-system.csv

...will do the same thing on Windows XP as it will on Vista or Windows 2008. Now, you have a nice comma-separated value file that you can open in Excel or parse with Perl, and include the entries in a timeline.

Okay, that's live response...what about post-mortem analysis? Well, it turns out that there's a couple of ways you can go on this issue. The first is to have a VM available for each version of Windows, or at least one on the Windows XP/2003 side, and one on the Vista/Windows 7 side. For example, you can mount or access an image of a Windows 2008 system on Windows 7 system, extract the .evtx files, and use the following command:

C:\tools>logparser -i:evt -o:csv "Select * from d:\cases\System.evtx" > system.csv

At this point, all you need to do is parse the resulting .csv file...Perl works quite nicely for this.

The other option is to use just Windows 2008 or Windows 7 as your analysis platform, and convert the .evt files to .evtx format using wevtutil.exe.

C:\tools>wevtutil epl AppEvent.evt AppEvent.evtx /lf:true

This gives you the ability to parse both .evt and .evtx formats on the same platform. However, if you're primarily interested in producing a timeline of events, the timeline tools from the Win4n6 Yahoo group contain a Perl script that parses .evt files into TLN format, without relying on the API. Also, the timeline tools for parsing .evt files will be able to extract event records that aren't "seen" by the API.


BenW said...


What events will not be seen by the API?

H. Carvey said...


The ELF_LOGFILE_HEADER structure has a two fields that determine where, in the "ring buffer" structure of the Event Log file, the current and oldest records are located. Based on this, I have seen where an entire event record has been found in this "dead space", and has not been seen by the API. Others have reported similar findings.