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

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

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The SonicWall Capture Labs Threat Research Team gathers, analyzes and vets cross-vector threat information from the SonicWall Capture Threat network, consisting of global devices and resources, including more than 1 million security sensors in nearly 200 countries and territories. The research team identifies, analyzes, and mitigates critical vulnerabilities and malware daily through in-depth research, which drives protection for all SonicWall customers. In addition to safeguarding networks globally, the research team supports the larger threat intelligence community by releasing weekly deep technical analyses of the most critical threats to small businesses, providing critical knowledge that defenders need to protect their networks.