The double free mach port bug: The short story of a dead 0day

The iOS 8 security update bulletin has many fixed bugs, one of which is this one: A double free issue existed in the handling of Mach ports. This issue was addressed through improved validation of Mach ports. CVE-2014-4375 : an anonymous researcher. Well, I’ve known this bug for a while and it was insanely fun as anti-debugging measure because of its random effects when triggered. For example, sometimes you get an immediate kernel panic, others nothing happens, and most of the time you get weird CPU spikes not attributed to any process, or system lock ups after a while. [Read More]

Shakacon #6 presentation: Fuck you Hacking Team, From Portugal with Love.

Aloha, Shakacon number 6 is over, it was a blast and I must confess it beat my expectations. Congratulations to everyone involved in making it possible. Definitely recommended if you want to speak or attend, and totally worth the massive jet lag. My presentation was about reverse engineering Hacking Team OS X malware latest known sample. The slide count is 206 and I was obviously not able to present everything. The goal is that you have a nice reference available for this malware and also MPRESS unpacking (technically dumping). [Read More]

About the processor_set_tasks() access to kernel memory vulnerability

At BlackHat Asia 2014, Ming-chieh Pan and Sung-ting Tsai presented about Mac OS X Rootkits (paper and slides). They describe some very cool techniques to access kernel memory in different ways than the usual ones. The slides and paper aren’t very descriptive about all the techniques so this weekend I decided to give it a try and replicate the described vulnerability to access kernel memory. The access to kernel task (process 0) was possible before Leopard (or was it fixed in Snow Leopard? [Read More]

Revisiting Mac OS X Kernel Rootkits Phrack article is finally out!

Enjoy it at Phrack. It’s finally out. It feels a bit old and it is indeed a bit old but still a good paper (or at least I tried to make it that way). The supplied code is for an older version of that rootkit. For example it still has dependencies on importing task, proc and other kernel private structures. The updated version solves all required offsets so it supports easily new and old OS X versions. [Read More]

Rex vs The Romans – Anti Hacking Team Kernel Extension

After surviving the five shots at SyScan’s WhiskeyCon I am finally back home and you get a chance to see the slides and code for the TrustedBSD module I presented there. The goal of REX vs The Romans is to work as detection and prevention tool of _Hacking Team_’s OS X malware. The TrustedBSD hook allows to detect if the system is already infected, and the Kauth listener to warn about any future infection. [Read More]

Teaching Rex another TrustedBSD trick to hide from Volatility

Rex the Wonder Dog (here and here) is a proof of concept that uses TrustedBSD framework to install kernel level backdoors. Volatility is able to detect these malicious modules with a plugin created by Andrew Case. The plugin works by looking up the TrustedBSD structures and dumping information about the loaded modules. At SyScan360 I presented a “new” trick to bypass this plugin by creating a shadow structure and leaving the legit one untouched. [Read More]

Don’t die GDB, we love you: kgmacros ported to Mavericks.

Our lovely GDB has been declared dead with Xcode 5 release. The new king in town is LLDB, and that also applies to kernel debugging. Change is good, even if we Humans don’t like it, but… there’s still no gdbinit for LLDB and I just love it. Even more important (for kernel debugging), LLDB still has no support (afaik) for VMware GDB stub. This means it’s not possible to do kernel debugging in Mavericks VMs other than KDP. [Read More]

Analysis of CoinThief/A "dropper"

There is no such thing as malware in OS X but last week another sample was spotted and made the “news”. I am talking about CoinThief, a malware designed to hijack Bitcoin accounts and steal everything (I must confess I laughed a bit; I think Bitcoin is just a bullshit pyramid scheme but I digress). There are a few samples out there, in different stages of evolution, so this is probably not a very recent operation. [Read More]

AppleDoesntGiveAFuckAboutSecurity iTunes Evil Plugin Proof of Concept

Oh this one has been into my head for so long that I finally decided to try and create the code for it. So let’s go! What’s the background story? In August 2011 I reported to Apple a security issue with iTunes. What happens is that iTunes plugins are loaded into iTunes process space so they have full control of iTunes. Evil plugins can do all kinds of things such as stealing iTunes passwords and credit card information, or patching some annoying features as I did with Disable m3u plugin. [Read More]

Updated version of Onyx The Black Cat

New version available at the github repo, compatible with Mavericks and with a Cocoa app to control its features. Mavericks sysent table is modified so previous versions weren’t compatible with it. I updated the sysent table definitions. It’s not the best method to assure future compatibility in case Apple decides to change the structure again. A better way is to find the symbols for the syscalls and replace them directly in the sysent table. [Read More]