alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE X-Panel CnC Activity"; flow:established,to_server; http.header_names; to_lowercase; content:"|0d 0a|x-panel-"; fast_pattern; http.header; content:"X-Panel-"; pcre:"/^(?:Callback|Internal)\x3a\x20\d[\r\n]/R"; reference:md5,77efad936a01ed754dcfeae281d7d521; classtype:command-and-control; sid:2071959; rev:1; metadata:affected_product Windows_Client, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_09_08, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Critical, tag c2, updated_at 2026_09_08, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)