I don’t remember which podcast or who said it, but “Garbage In Gospel Out” is so true. Especially when talking about Cyber Threat Intelligence. I talked a little about this before, both in conference talks and in Validate Data Before Sharing.
But here it is, three years later, and the problem remains. I’m willing to say it is getting worse. We’re not running full life cycles, either Intelligence or Incident Response. We get to the collection phase and call it done. NixIntel has a good post on that at their blog.
About a month ago, I added a couple shell scripts to my DFIR Github repository. Three of the four scripts are used at work daily in either a Linux terminal, or a Cygwin terminal. The fourth script is something I use to help with quarantined mail, and not really DFIR based.
b64Decode.sh and hexConvert.bash take command line arguments and reports back the result. For example:
The first extractor script, xHttpExtractor.py came about from a web based tool I used. It would run on a file uploaded to it, and then list a bunch of indicators, system artifacts, url calls outs, network communication, etc. However the tool didn’t have a good export mechanism at the time. So I would copy and paste everything to a text file, and then extract the url host details from the text files. Mainly so I could add the URL indicators to the web proxy.
I re-wrote a script I use at work. It was a messy bit of Python 3 previously. While it’s still not the cleanest of python scripts, it scratches my itch. It was originally just a straight line of commands with lots of repeated code. I made some functions and made it a little more modular. I know I need to learn PEP8, and start following it. This was just to improve something that I wrote previously with things I learned from Automate the Boring Stuff with Python.
I’ve shared it via my GitHub repository for DFIR scripts. They’re clean (not tied to any company). There is only Computer Ping for right now. There are 3 scripts all based on the same idea.
Ping a computer, if it is down, keep trying every 10 minutes for 1 hour. Pop an “alert” if the target is up, or the script finished before it came up.
1 version for Windows running python (wComputerPing.py)
1 version for Windows running Cygwin (cwComputerPing.py)
1 version for boxes running Linux. (lComputerPing.py).
I’ll write others and upload to the repository as I have time / re-write stuff I use. They might not all be Python, but my goal is to be more Python than not.
Has anyone else noticed that Bing has lots of Domain Generation Algorithm (DGA) links in the search results? it isn’t on every search, just some searches. But the same search result at Google doesn’t return the DGA links.
Click this Panic button to reset everything. Go look at this pcap in Wireshark. Run this command in cmd.exe (and even walks the student through opening a term window by go to the start button, type cmd in the run box).
Run Snort with the test option on a pre-defined rule set using the pcap you looked at. Modify the same rule multiple times, enabling and disabling an alert each time. Run to see the difference.
Answer these 10 questions.
The last question was how to improve the class… I forgot to say use a Linux VM instead of a Windows VM. Since one of my answers did require Grep. Which means copy and paste from the VM lab to my box connected to the lab.