alert http $HOME_NET any -> $EXTERNAL_NET 443 (msg:"ET MALWARE APT Lurker POST CnC Beacon"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".php"; fast_pattern; pcre:"/\.php$/"; http.header; content:"HOST|3a|"; depth:5; content:"User-Agent|3a|"; distance:0; pcre:"/^Host\x3a[^\r\n]+\r\nUser-Agent\x3a[^\r\n]+\r\nContent-Length\x3a\x20\d+\r\n(?:\r\n)?$/mi"; http.header_names; content:!"Content-Type|0d 0a|"; content:!"Accept"; content:!"Referer|0d 0a|"; reference:md5,c5a8e09295b852a6e32186374b66e1a7; reference:url,blogs.rsa.com/wp-content/uploads/2015/05/RSA-IR-Case-Study.pdf; classtype:targeted-activity; sid:2021584; rev:7; metadata:attack_target Client_Endpoint, created_at 2015_08_03, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_11_19, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)