Fax Service DLL Search Order Hijack
This rule detects attempts to exploit a DLL search order hijacking vulnerability in the Windows Fax service. Specifically, it looks for instances where the 'fxssvc.exe' process attempts to load 'ualapi.dll' from a location other than the legitimate Windows system directories (e.g., 'C:\Windows\WinSxS\'). This indicates that an attacker may have placed a malicious 'ualapi.dll' in a directory that the Fax service searches before the legitimate system path, leading to the execution of the attacker's code.
Sigma
