As time goes on operating systems keep evolving, like Microsoft Windows do, it ships new designs, features and codes from time to time. However sometimes it also ships more than bit of codes for complex subsystems residing in its kernel ... and at some future point it starts implementing new designs to prevent unnecessary access to it. However is it safe enough?



As we can see from security bulletins, win32k subsystem attracts lots of attention. It looks that with efforts of many security researchers who has dug into this area, finding bugs here shall becomes pretty tough and almost fruitless. But unfortunately this is not true, as win32k is backed up by very complex logic and large amount of code by nature..



We will present our point of view to Windows graphic subsystem, as well as schema of our fuzzing strategies. We will introduce some unusual areas of win32k, its extensions and how it can breaks even locked environments.



Part of our talk will be dedicated to CVE-2016-0176, the bug we used for this year's Pwn2Own Edge sandbox bypass, from its discovery to its exploitation techniques, which could serves as an example for universal DirectX escape which is independent of graphics vendors.