Root privilege escalation via untrusted onstat execution

Privilege escalation in the Checkmk mk_informix agent plugin allows local users to execute attacker-controlled code as root. The root-run plugin evaluates statements parsed from $INFORMIXDIR/bin/onstat, searches its bin directory before $PATH, and executes a substituted onstat as root. Exploitation requires local control over onstat or a same-named executable in that directory and grants root-level command execution.