The rule identifies the use of PowerShell scripts that employ .NET functionalities for decompressing and Base64 decoding. This detection is crucial as malware often utilizes these techniques to obfuscate payloads, loading them into memory to evade security mechanisms. By monitoring processes running on Windows systems over the past nine months, the rule leverages specific PowerShell script patterns to trigger alerts when such suspicious activity is detected. It focuses on identifying scripts that import certain compression functionality and use the `FromBase64String` method, which are common indicators of obfuscation techniques used by attackers. Recommendations for investigating triggers include analyzing script content, process execution chains, and associated network activities. The rule also details the setup necessary for implementing PowerShell Script Block Logging. Overall, it highlights the need to investigate further into suspicious user activity and potential malware presence within systems.