Reversing Apple’s syslogd bug

Two days ago El Capitan 10.11.3 was released together with security updates for Yosemite and Mavericks. The bulletin available here describes nine security issues, most of them related to kernel or IOKit drivers. The last security issue is about a memory corruption issue on syslog that could lead to arbitratry code execution with root privileges. I was quite curious about this bug mostly because it involved syslogd, a logging daemon....

January 22, 2016 · 7 min · 1490 words

Gatekeerper – A kernel extension to mitigate Gatekeeper bypasses

Last month Patrick Wardle presented Exposing Gatekeeper at VB2015 Prague. The core of the presentation deals with Gatekeeper bypasses originating in the fact that Gatekeeper only verifies the code signatures of the main binary and not of any linked libraries/frameworks/bundles. This means it is possible to run unsigned code using dynamic library hijacking techniques also presented by Patrick in code that should be protected by Gatekeeper. His exploit uses an Apple code signed application that is vulnerable to dylib hijacking and is modified to run unsigned code when downloaded from the Internet....

November 9, 2015 · 12 min · 2463 words

London and Asia EFI monsters tour!

Finally back home from China and Japan tour, so it’s time to finally release the updated slides about EFI Monsters. After Secuinside I updated them a bit, fixing stuff I wasn’t happy with and adding some new content. The updated version was first presented at 44CON London. I had serious reservations about going to the UK (not even in transit!) but Steve Lord and Adrian charm convinced me to give it a try....

November 6, 2015 · 3 min · 498 words

Writing Bad @$$ Lamware for OS X

The following is a guest post by noar (@noarfromspace), a long time friend. It shows some simple attacks against BlockBlock, a software developed by Patrick Wardle that monitors OS X common persistence locations for potential malware. The other day noar was telling me about a few bypasses he had found so I invited him to write a guest post. The title is obviously playing with one of Patrick’s presentations. I met Patrick at Shakacon last year and this is not an attempt to shame him (that is reserved mostly for Apple ;-))....

August 7, 2015 · 5 min · 984 words

Reversing Prince Harming’s kiss of death

The suspend/resume vulnerability disclosed a few weeks ago (named Prince Harming by Katie Moussouris) turned out to be a zero day. While (I believe) its real world impact is small, it is nonetheless a critical vulnerability and (another) spectacular failure from Apple. It must be noticed that firmware issues are not Apple exclusive. For example, Gigabyte ships their UEFI with the flash always unlocked and other vendors also suffer from all kinds of firmware vulnerabilities....

July 1, 2015 · 31 min · 6439 words