This indicates an attack attempt against a remote command-execution vulnerability in phpSlash.
A vulnerability has been reported in phpSlash 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 field parameter value that is passed to "index.php". An attacker may include shell commands by supplying an injection string through the URL.
PHPSlash 0.8.1 1
System Compromise: Remote attackers can gain control of vulnerable systems.
Currently we are not aware of any patches supplied by the vendor for this issue.