By leveraging and modifying a “semi-random public exploit” researchers have managed to deactivate all protection features of the latest version of Microsoft’s Enhanced Mitigation Experience Toolkit and “get shell” on the target system and execute code.
This is not the first time that researchers have managed to bypass EMET’s protections, but Offensive Security’s experts have decided on trying another approach: disarming the tool altogether.
And they were able to do it by changing a specific and easily accessible global variable in the .data section of the EMET.dll via a ROP chain. Then it only remained to disarm the tool’s Export Access Filtering (EAF) mitigation feature, which they managed to do using a method previously published by another researchers.
“We have not seen this method of bypassing EMET in public exploits, however we do believe that Microsoft became aware of it as it has been corrected in Technical Preview versions of EMET 5 and greater,” the researchers noted.
“What this shows is that while EMET is definitely a good utility and raises the bar for exploit developers, it is not a silver bullet in stopping these types of attacks.”
EMET 5 Technical Preview can be downloaded here.