Detectionhightest

Webshell Tool Reconnaissance Activity

Detects processes spawned from web servers (PHP, Tomcat, IIS, etc.) that perform reconnaissance looking for the existence of popular scripting tools (perl, python, wget) on the system via the help commands

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Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.

Launch

Cian Heasley, Florian Roth (Nextron Systems)Created Wed Jul 22Updated Thu Nov 09f64e5c19-879c-4bae-b471-6d84c8339677windows

Log Source

WindowsProcess Creation

ProductWindows← raw: windows

CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic

detection:
    selection_webserver_image:
        ParentImage|endswith:
            - '\caddy.exe'
            - '\httpd.exe'
            - '\nginx.exe'
            - '\php-cgi.exe'
            - '\w3wp.exe'
            - '\ws_tomcatservice.exe'
    selection_webserver_characteristics_tomcat1:
        ParentImage|endswith:
            - '\java.exe'
            - '\javaw.exe'
        ParentImage|contains:
            - '-tomcat-'
            - '\tomcat'
    selection_webserver_characteristics_tomcat2:
        ParentImage|endswith:
            - '\java.exe'
            - '\javaw.exe'
        CommandLine|contains:
            - 'CATALINA_HOME'
            - 'catalina.jar'
    selection_recon:
        CommandLine|contains:
            - 'perl --help'
            - 'perl -h'
            - 'python --help'
            - 'python -h'
            - 'python3 --help'
            - 'python3 -h'
            - 'wget --help'
    condition: 1 of selection_webserver_* and selection_recon