This rule is designed to detect suspicious usage of the Windows 'rundll32.exe' process when it is invoked with command line arguments containing uncommon or unexpected DLL extensions. 'rundll32.exe' is frequently exploited by attackers to execute arbitrary code stored in dynamically linked libraries (DLLs). The rule aims to monitor instances where 'rundll32' is executed, filtering out various common, expected command line patterns, such as those containing known extensions (like .dll, .cpl, .inf) or typical maintenance tasks (like ' -localserver '). It also disregards executions initiated by recognized legitimate processes, such as 'msiexec.exe', to minimize false positive alerts. By focusing on less common command line patterns, the rule can help identify possibly malicious behavior or attempts to evade detection during malware execution. This detection is critical given that attacks using 'rundll32.exe' can be part of broader evasion strategies to exploit user systems while attempting to thwart standard security checks.