The rule "Potential Shell via Web Server" is designed to identify suspicious command executions originating from web servers, which could indicate the presence of a web shell. A web shell is a malicious PHP/CGI script uploaded to a server that allows remote command execution. By monitoring process activity related to common scripting languages (.bash, .python, etc.) executed by web server processes (like Apache or Nginx), the rule aims to detect potential backdoor entry points for attackers. It includes detailed investigation steps focusing on abnormal behavior, command line analysis, and correlation with other alerts, while also providing guidance on response and remediation actions to mitigate risks associated with identified threats. As the detection rule has reached a deprecation date, organizations are encouraged to migrate to updated rule sets for continued protection.