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Windows MsMpEng Writing to System32

Detects MsMpEng.exe creating a file in C:\\Windows\\System32\\. This should never happen under normal operation Windows Defender does not install kernel drivers at runtime. In the BlueHammer exploit, the TOCTOU race…

Description

Detects MsMpEng.exe creating a file in C:\\Windows\\System32\\. This should never happen under normal operation Windows Defender does not install kernel drivers at runtime. In the BlueHammer exploit, the TOCTOU race causes MsMpEng (SYSTEM) to write the attacker's driver payload directly into the drivers directory.

Detection logic

Detection requirements

Platform
ContainersLinuxmacOSWindows

The rule states no platform. This is derived from the 2 ATT&CK techniques it maps to.

Known benign triggers

  • No false positives have been identified at this time.

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