alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET EXPLOIT Unknown Target Application Command Injection Inbound"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/nrdh.php?cmd"; fast_pattern; content:"="; distance:0; within:3; pcre:"/^.{0,5}(?:\x3b|\x0a|\x26|\x60|\x7C|\x24)/R"; classtype:attempted-admin; sid:2033759; rev:1; metadata:attack_target Server, created_at 2021_08_22, deployment Perimeter, deployment Internal, confidence Medium, signature_severity Major, tag Exploit, updated_at 2021_08_22, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;)