Microsoft Excel Add-In Loaded From Uncommon Location
This rule detects when Microsoft Excel loads an Add-In (.xll) file from an uncommon or potentially suspicious location. Adversaries often use XLL files for initial access or execution by embedding malicious code within them, and loading them from non-standard directories like Desktop, Downloads, Temp, or Public user folders can indicate malicious activity. The rule specifically looks for excel.exe loading an .xll file from a predefined list of suspicious directories.
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