Black Hat USA 2015: Breaking Windows

Windows 10 goes some way toward defeating client-originating Pass-the-Hash attacks, but widely deployed legacy protocols like Kerberos and NTLM will be vulnerable for many years to come. Can Pass-the-Hash be stopped in such a vulnerable environment? Defeating Pass-the-Hash: Separation of Powers will delve into Windows 10's solution: a new level of OS isolation, based on virtualization technology, that allows hashes and other secrets to be hidden even from the kernel. But how realistic is this scheme, and will it hold together in practice?

Another recent exploit mitigation technique is Control Flow Guard (CFG), which first appeared in Windows 8.1 Update 3. CFG checks the target of an indirect call and raises an exception if the target is invalid, thus preventing a vital step of many exploit techniques. Bypass Control Flow Guard Comprehensively will show that CFG has a major weak point that allows for its bypass, once again enabling the old exploits. To make things worse, this technique leaves the door open for further such exploits to be developed.

With Windows 10, Internet Explorer finally steps aside in favor of EdgeHTML ("Project Spartan"), Microsoft's new web rendering engine. Edge will be everywhere soon enough, so Understanding the Attack Surface and Attack Resilience of Project Spartan's New EdgeHTML Rendering Engine will foster a better understanding of this new technology's attack surface. Mark Vincent Yason will explain how EdgeHTML compares to the previous MSHTML to identify new attack surfaces, show its new exploit mitigations, and identify which bypass techniques are still working and valid.

Finally, what if every Windows OS back to '95 hosted a technology that runs as System, executes arbitrary code, persists across reboots, and doesn't drop a single file to disk? Oh, you mean Windows Management Instrumentation (WMI)! Abusing Windows Management Instrumentation (WMI) to Build a Persistent Asynchronous and Fileless Backdoor will show how an attacker practicing a minimalist methodology can blend into their target environment without dropping a single utility to disk, and execute code asynchronously in response to OS events. Beyond the basics, Matthew Graeber will explain how attackers are using WMI today and how to detect and mitigate such attacks.

Black Hat USA 2015 will occur at the Mandalay Bay resort in Las Vegas. It goes down August 1-6, so be sure to register to lock in your attendance.