Detection rules › Splunk

Windows DLL Side-Loading In Calc

Author

Teoderick Contreras, Splunk

Source

upstream

The following analytic detects the loading of the "WindowsCodecs.dll" by calc.exe from a non-standard location This could be indicative of a potential DLL side-loading technique. This detection leverages Sysmon EventCode 7 to identify the DLL side-loading activity. In previous versions of the "calc.exe" binary, namely on Windows 7, it was vulnerable to DLL side-loading, where an attacker is able to load an arbitrary DLL named "WindowsCodecs.dll". This technique has been observed in Qakbot malware. This activity is significant as it indicates potential malware execution through a trusted process, which can bypass security controls. If confirmed malicious, this could allow attackers to execute arbitrary code, maintain persistence, and escalate privileges within the environment.