Webshell Tool Reconnaissance Activity
A Sigma rule for process creation on Windows, by Cian Heasley, Florian Roth (Nextron Systems).
high 1 ATT&CK technique 3 programs it names
What it looks for
detection:
selection_recon:
CommandLine|contains:
- 'perl --help'
- 'perl -h'
- 'python --help'
- 'python -h'
- 'python3 --help'
- 'python3 -h'
- 'wget --help'
selection_webserver_characteristics_tomcat1:
ParentImage|contains:
- '-tomcat-'
- '\tomcat'
ParentImage|endswith:
- '\java.exe'
- '\javaw.exe'
selection_webserver_characteristics_tomcat2:
CommandLine|contains:
- 'CATALINA_HOME'
- 'catalina.jar'
ParentImage|endswith:
- '\java.exe'
- '\javaw.exe'
selection_webserver_image:
ParentImage|endswith:
- '\caddy.exe'
- '\httpd.exe'
- '\nginx.exe'
- '\php-cgi.exe'
- '\w3wp.exe'
- '\ws_tomcatservice.exe'
condition: 1 of selection_webserver_* and selection_recon
The rule’s detection, its selections and fields in order of name. The whole rule, with its references and false positives, is on SigmaHQ, by Cian Heasley, Florian Roth (Nextron Systems), under the Detection Rule License 1.1. CmdID evaluates it on a command line alone: a test on what a command line cannot show, such as the parent process or the user, is not met.
None of the everyday examples and documented commands on CmdID’s program pages trips it. To see whether a command line does, paste it into CmdID.
Programs and files it names
ATT&CK
T1505.003Server Software Component: Web Shell