source: https://www.securityfocus.com/bid/14091/info

imTRBBS is affected by a remote command execution vulnerability.

Specifically, an attacker can supply arbitrary commands prefixed with the '|' character through the 'im_trbbs.cgi' script that will be executed in the context of the Web server running the application.

This issue is reported to affect imTRBBS version 1.02; other versions may also be vulnerable. 

http://www.example.com/cgi-bin/im_trbbs.cgi?uid=parameter&df=bbs.dat|ls|