Type Confusion Vulnerability in Microsoft Security Products CVE-2017-0290

May 11, 2017

A few days ago, Google Security Research published a POC detailing a vulnerability in Microsoft's Malware Protection service's MsMpEng engine.

The main component is called mpengine.dll. This is responsible for scanning and analyzing various files. It contains various interpreters and emulators for analyzing various file formats, compression and encryption algorithms.

Scanning the provided POC using Windows 7's Windows Defender, we get the following crash notification:

After restarting, and checking the running processes from the task manager, we concluded that MsMpEng was not present for this setup. We then checked the services tab of task manager and found the following:

Searching the PID 3420 in the process list, we see that the service is attached to svchost.exe:

We then attached the debugger to this instance of svchost and attempted to scan the POC.

As it turns out, the vulnerable function is found in mpengine.dll's MPContainerWrite.

SonicWALL Threat Research Team has researched this vulnerability and have the following signatures in place to protect their customers:

  • SPY 1468: Malformed-File js.MP.3