Apple EFI firmware passwords and the SCBO myth

My original goal when I started poking around Apple’s EFI implementation was to find a way to reset a MacBook’s firmware password. My preliminary research found references to a “magical” SCBO file that could be loaded onto a USB flash drive and booted to remove the password. The normal process workflow is to first contact Apple support. Since I don’t have the original sales receipt of this specific Mac, I assume this option isn’t possible, since anyone with a stolen Mac could get the password reset. Things got more interesting when I found a website that allegedly sold the SCBO files – just send them the necessary hash (more on this later), pay USD100, and get a working SCBO file in return. There are videos (in Portuguese but you can watch the whole process) of people claiming this works, and even some claims about an universal SCBO that unlocks multiple Macs.

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SyScan360 Singapore 2016 slides and exploit code

The exploit for the bug I presented last March at SyScan360 is today one year old so I decided to release it. I wasn’t sure if I should do it or not since it can be used in the wild but Google Project Zero also released a working version so it doesn’t really make a difference. I’m also publishing here the final version of the slides that differ slightly from the version made available at the corporate blog. [Read More]

The Italian morons are back! What are they up to this time?

Nothing 😃. HackingTeam was deeply hacked in July 2015 and most of their data was spilled into public hands, including source code for all their sofware and also some 0day exploits. This was an epic hack that shown us their crap internal security but more important than that, their was of doing things and internal and external discussions, since using PGP was too much of an annoyance for these guys (Human biases are a royal pain in the ass, I know! [Read More]

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. [Read More]

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. [Read More]

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. [Read More]

Rootfool – a small tool to dynamically disable and enable SIP in El Capitan

El Capitan is finally released and System Integrity Protection aka SIP aka rootless is finally a reality we must face. Let me briefly describe SIP (technical details maybe in another post, now that El Capitan is final and out of NDAs). This post by Rich Trouton contains a very good description of its userland implementation and configuration. What is SIP anyway? The description that I like to use is that SIP is a giant system-wide sandbox, that controls access to what Apple considers critical files and folders. [Read More]

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 ;-)). [Read More]

BSides Lisbon and SECUINSIDE 2015 presentations

I guess my goal for the remaining 2015 of not doing any presentations will not happen. Two weeks ago I presented at BSides Lisbon 2015 and last week at SECUINSIDE 2015. I’m very happy to see BSides Lisbon returning after the first edition in 2013. Congrats to Bruno, Tiago, and the rest of the team for making it happen. It’s still a small conference but I’m glad they are making it happen, and I will always do my best to help the Portuguese scene going forward. [Read More]

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. [Read More]