alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE OnionDrop CnC Activity (POST)"; flow:established,to_server; http.method; content:"POST"; http.uri; bsize:11; content:"/nfront.php"; fast_pattern; http.header_names; content:!"|0d 0a|referer|0d 0a|"; nocase; reference:url,cyderes.com/howler-cell/oniondrop-malware-analysis; reference:md5,77efad936a01ed754dcfeae281d7d521; classtype:trojan-activity; sid:2071886; rev:1; metadata:affected_product Windows_Client, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_09_01, deployment Perimeter, deployment SSLDecrypt, malware_family OnionDrop, confidence High, signature_severity Critical, tag c2, updated_at 2026_09_01, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)