alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/CHIP Ransomware CnC Checkin"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".php"; http.host; pcre:"/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}(?:\x3a)?/"; http.request_body; content:"-----BEGIN CERTIFICATE-----"; depth:27; fast_pattern; content:"-----END CERTIFICATE-----"; distance:0; http.content_type; content:"application/x-www-form-urlencoded"; startswith; http.header_names; content:!"Accept"; content:!"Referer|0d 0a|"; reference:md5,18189daa96e711777158d7cb599c13b1; reference:url,malware-traffic-analysis.net/2016/11/17/index.html; classtype:command-and-control; sid:2023534; rev:4; metadata:attack_target Client_Endpoint, created_at 2016_03_07, deployment Perimeter, malware_family Win32_CHIP, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_03, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;)