NoSuchCon’13 and crashing Windows with two instructions

The first edition of the NoSuchCon security conference held in Paris ended just a few days ago. Before anything else, I would like to thank all of the organizers (proudly listed at for making the event such a blast! Both the location, venue and speaker line-up were amazing, with lots of free beer and wealth of people to chat with. Overall, I am very happy to have shown up there and I will definitely make sure to attend the second edition of the conference.

Other than drinking, discussing 0-days and visiting Paris, I also had the pleasure to give a talk about the usual subject – Windows kernel security. The exact title of my presentation was “Abusing the Windows Kernel: How to Crash an Operating System With Two Instructions“, and touched on the subject of several different exploitation techniques, internal CPU related behavior and security vulnerabilities (all related to the Windows operating system) that I discovered during the course of last several weeks / months.

While the slide deck was made available to the attendees right at the beginning of my talk at (great idea!), I’m reposting them here anyway, in case you haven’t had a chance to take a look yet. In fact, a majority of the talks were interesting and highly technical, so be sure to check the available material for all presentations ;-)

Slides: “Abusing the Windows Kernel: How to Crash an Operating System With Two Instructions” (3.3MB, PDF)

KiTrap0e advisory: “Abusing Windows NT #PF Trap Handler to Bugcheck and Leak Information

Read more

SyScan 2013, Bochspwn paper and slides

(Collaborative post by Mateusz “j00ru” Jurczyk and Gynvael Coldwind)

A few days ago we (Gynvael and I) gave a talk during the SyScan’13 conference in the fine city of Singapore, and as promised (though with a slight delay), today we are publishing both the slide deck and a white paper discussing memory access pattern analysis – a technique we recently employed with success to discover around 50 double-fetch vulnerabilities in Windows kernel and related drivers (Elevation of Privileges and Denial of Service class; see Microsoft Security Bulletins MS13-016, MS13-017, MS13-031 and MS13-036 released in February and April this year. Also, stay tuned for more security patches in May and June).

In our SyScan presentation, we explained the concept of kernel race conditions in interacting with user-mode memory, gave a brief rundown on how they can be identified by using CPU-level instrumentation of an operating system session, and later focused on how they can be successfully exploited with the help of several generic techniques (on the example of three Windows vulnerabilities discovered by the Bochspwn project). While we only had the time to go through a single case study (the CVE-2013-1254 vulnerability in win32k!SfnINOUTSTYLECHANGE), both slides and the paper contain a detailed analysis of another local privilege escalation: CVE-2013-1278 in nt!ApphelpCacheLookupEntry, and an amusing case of a double fetch behavior (it is not clear if it can be classified as a bug) found in the default kernel implementation of the standard nt!memcmp function, as a bonus.

We hope you will enjoy both the slides and whitepaper – considering the amount of time we have dedicated to the research, we would really appreciate your feedback.


Read more