This indicates an attack attempt against a remote command-execution vulnerability in phf, which is a sample cgi bin program.
A vulnerability has been reported in phf that may allow an attacker to execute shell commands on a vulnerable system. This is possible because the user input filters fail to properly sanitize the "Qname" parameter value. An attacker may include shell commands by supplying an injection string through the URL.
NCSA httpd 1.5 a-export
Apache Software Foundation Apache 1.0.3
System Compromise: Remote attackers can execute arbitrary code in vulnerable systems.
Upgrade to the latest version, available from the following web site: