source: https://www.securityfocus.com/bid/2056/info

Hylafax is a popular fax server software package designed to run on multiple UNIX operating systems. Unpatched version of Hylafax ship with an insecure script, faxsurvey, which allows remote command execution with the privileges of the web server process. This can be exploited simply by passing the command as a parameter to the script - see exploit. Consequences could include web site defacements, exploiting locally accessible vulnerabilities to gain further privileges, etc. 


http://target.host/cgi-bin/faxsurvey?/bin/cat%20/etc/passwd