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Windows Office Product Loaded MSHTML Module

The following analytic detects the loading of the mshtml.dll module into an Office product, which is indicative of CVE-2021-40444 exploitation. It leverages Sysmon EventID 7 to monitor image loads by specific Office…

Description

The following analytic detects the loading of the mshtml.dll module into an Office product, which is indicative of CVE-2021-40444 exploitation. It leverages Sysmon EventID 7 to monitor image loads by specific Office processes. This activity is significant because it can indicate an attempt to exploit a vulnerability in the MSHTML component via a malicious document. If confirmed malicious, this could allow an attacker to execute arbitrary code, potentially leading to system compromise, data exfiltration, or further network penetration.

Detection logic

Detection requirements

Platform
LinuxmacOSWindows

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

Log source category
sysmon_eventid_7

Known benign triggers

  • Limited false positives will be present, however, tune as necessary. Some applications may legitimately load mshtml.dll.

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