I always had some strange attraction to rootkits and was thrilled to hear that Crisis had one. This chapter is dedicated to the rootkit implementation, its tricks and how it’s controlled (and its fuckups!). A small disclosure note about me making fun of Italians on Twitter. I love Italy and have nothing against Italians. We just share some cultural things that I really hate and that’s the reason why I was making fun of Crisis origins and some of its design/features. [Read More]
Tales from Crisis, Chapter 2: Backdoor’s first steps
Let’s continue our cute story about OS.X/Crisis, this time with the startup flow of the main backdoor module. Please apologize for the delay on this chapter – I had some fun with the rootkit and that diverted me to other things. The first curious detail about the backdoor module (installed as /Users/USERNAME/Library/Preferences/jlc3V7we.app/IZsROY7X.-MP) is that no obfuscation/anti-debugging tricks are used (except one) so its analysis is easier than the dropper. It also uses Objective-C heavily, which is still a bit annoying in IDA but has the advantage of the code being very descriptive. [Read More]
Tales from Crisis, Chapter 1: The dropper’s box of tricks
Mac malware is back to news spotlight, this time with Crisis (insert one of the other thousand names here _____). This malware is nothing more than commercial spy software being sold by a lot of money to governments or something (oh boy, I could make a good living out of this). I’m lucky enough to have a sample of it (thank you, you know who you are!) and also lucky to be able to talk about it (it uses some similar tricks that I knew about). [Read More]
A small improvement to OS X “rootkitery”: bruteforcing sysent discovery, fast & easy!
I love to read about the Human brain and yesterday I was feeling weird about this thing. As far as I know, everyone (publicly) was trying to search sysent in one way or another after Apple removed the sysent symbols but not bruteforcing it. It seems no one bothered to question the original method (Landon Fuller?) and just kept using it. Are there any historical reasons for this? I can’t remember any. [Read More]
Fixes for the TrustedBSD backdoor – Rex the wonder dog v0.2
I like things well done and the healthy discussion with snare about this topic remembered me this PoC was a bit incomplete. So I decided to close the missing gaps. The fix is pretty simple. Retrieve a new kauth credential with uid and gid equal to 0 and replace the old one (the code seems stable even without process locks). It also seems to work fine without the allproc lock. The backdoor also had a small “bug” that I didn’t noticed due to a coincidence. [Read More]
Abusing OS X TrustedBSD framework to install r00t backdoors...
While poking around OS X implementation of TrustedBSD to write the sandbox guide I had the idea of trying to abuse it for backdooring purposes. It’s kind of funny that something designed to protect can be so “easily” abused to install backdoors. This is not rocket science or a big breakthru post – I was just curious about the possibility to abuse the framework. You still need to find a way to install the kernel module! [Read More]