alert http [$HOME_NET,$HTTP_SERVERS] any -> $EXTERNAL_NET any (msg:"ET ATTACK_RESPONSE Possible arp command output via HTTP (Linux Style)"; flow:established,to_client; http.response_body; content:!"<html"; content:"|29 20|at|20|"; content:"|20 5b|ether|5d 20|on|20|"; fast_pattern; distance:17; within:12; classtype:successful-recon-limited; sid:2049391; rev:1; metadata:attack_target Server, created_at 2023_11_29, deployment Perimeter, performance_impact Low, confidence Low, signature_severity Major, tag WebShell, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_11_29, mitre_tactic_id TA0003, mitre_tactic_name Persistence, mitre_technique_id T1505, mitre_technique_name Server_Software_Component; target:src_ip;)