07/03/2014

how to disarm advanced windows protections (EMET) and take over a computer afterwards

"EMET is designed to prevent software vulnerabilities from being exploited by using various mitigation technologies, including Structured Exception Handler Overwrite Protection (SEHOP), Data Execution Prevention (DEP), Heapspray Allocations, Null page allocation, Mandatory Address Space Layout Randomization (ASLR), Export Address Table Access Filtering (EAF) and Return Oriented Programming (ROP) mitigations.

Research papers such as "Bypassing EMET 4.1" and "EMET 4.1 Uncovered" detail mitigation bypass methods, but Offensive Security has focused on disarming EMET, rather than on bypassing mitigations, as this method gives an attacker the ability use generic shellcodes such as the ones generated by Metasploit. This also represents a generic way of disabling all protections, and "not having to rely on functions that are not critical to EMET when trying to defeat the MemProt ROP protection, especially when having 'Deep Hooks' enabled," the company said.

The researchers managed to disarm EMET and get a shell after finding a global variable in the .data section of the EMET.dll file. The said variable, which is located on a memory page marked with read/write permissions, acts as a switch to enable or disable all the ROP protections at runtime.
http://www.securityweek.com/researchers-disarm-microsofts...

the article gives more information and links to the exploit code and a video tutorial

EMET is only the very last protection so it is even more important that your first defense (firewall, proxy, application control etc....) is strong and Advanced

EMET will not protect anymore if these défenses are bypassed or too lax.

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