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.
Shortly after rebuilding my Raspberry NAS last year, it stopped working again. The system wouldn’t boot right, even after changing the micro-SD card with a new build of Raspbian. A few weeks ago, I bought a new Pi 3 b and rebuilt the NAS again. When the system powered on, one of the USB drives wasn’t working. It looked like the file system was corrupt. During attempts to recover the USB drive, it stopped being readable. Both my Windows and Linux computers could see the USB drive, but not the file system, or the data. I re-formatted the disc drive, and it started working fine, it just had no data on it.
At work, we have this thing on Fridays called power up time. It is the last 4 hours of the week to work on personal projects, test new ideas to see if they are worth implementing, or self improvement. Most weeks it is when I get to look at the most tickets doing Tactical level intelligence since the rest of the week is filled with project or priority case work.
Recently while working on tactical level information for SOC tickets, I was able to add in a little fun, and actually power up. I wanted to do some reverse engineering of the malware associated with the ticket, to see if there was more IOCs that could be extracted.
Earlier in the day I read an email in the SANS DFIR alumni list, which included someone talking about using Remnux with docker. So later in the the day working the ticket, and because I didn’t have a Remnux box, I decided to check out the docker containers. This was also my first time working with docker as well. Starting at Lenny Zeltzer’sRemnux Docker Site.
I went to my linux vm, a box that gets reset to the fresh installed state via snapshot after each use. After a sudo apt install docker.io and a sudo docker pull remnux/pescanner I had the container.
I ran it and learned a little bit about docker. I also got an understanding of some of the information that VirusTotal displays under the detail tab.
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.