alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET DELETED Unknown Ransomware Checkin"; flow:established,to_server; content:"/index.html"; http_uri; content:"POST"; http_method; content:!"User-Agent|3a| "; http_header; content:"application/octet-stream|0d 0a 0d 0a|"; http_client_body; content:"/"; http_client_body; distance:2; within:1; pcre:"/filename=\x22\d+?\x22/P"; classtype:trojan-activity; sid:2016185; rev:3; metadata:attack_target Client_Endpoint, created_at 2013_01_12, deployment Perimeter, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;)