When good URLs are bad for business

Analyzing memory dumps comes with a price – ‘good’ information overload. One that annoys me a lot is running URl/domain extraction tools over the memdump and finding tones of legitimate URLs that make it harder to find the juicy stuff I am after. I mean, things like:

  • http://www.w3.org/2001/XMLSchema-instance
  • http://www.w3.org/2000/svg
  • http://www.w3.org/1999/xlink
  • http://www.w3.org/XML/1998/namespace
  • http://www.w3.org/1999/xhtml
  • http://www.w3.org/2000/xmlns/
  • http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd
  • http://update.microsoft.com
  • http://schemas.microsoft.com/rtc/2009/05/simplejoinconfdoc

There is a lot of ‘good’ URLs embedded in manifests, various resources (e.g. HTML/XML/Json/CSS files), certificates, and many are introduced as a side-effect of linking with static libraries that often include copyright information and URL to author’s page. And of course, there is vendor information either directly in the resources or in binary or its config files.

Not only memory dump analysis suffer from it. The same goes for network log analysis – lots of requests that ‘hide’ the juicy stuff are related to authentication checks, downloads from certificate stores, etc..

In an effort to help with analysis I started building a small repository of these ‘good’ URL (at the moment primarily related to certificates). I extracted these from my ‘good’ sample repository so I believe all of them are legitimate. If you find any error, please let me know.

You can download the repo here.

The Alexiou Principle

I very rarely republish content of other blogs, but today, for many reasons really, I feel obliged to republish one of the most relevant DFIR posts ever: The Alexiou Principle by Chris Pogue.

The 4 questions that form The Alexiou Principle are absolutely perfect:

  1. What question are you trying to answer?
  2. What data do you need to answer that question?
  3. How do you extract that data?
  4. What does that data tell you?

If you are starting your DFIR journey, or are a seasoned DFIR professional these questions will remain a mantra that you will follow, one way or another.

Embrace them.