alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32.Crypren/Zcrypt Ransomware Checkin"; flow:established,to_server; http.uri; content:".php?computerid="; pcre:"/\.php\?computerid=[a-fA-F0-9]{32}&(?:public|private)=\d$/"; http.header_names; content:!"Referer|0d 0a|"; reference:md5,7efb738c2b04aacdd3354d590cb3df47; classtype:command-and-control; sid:2022897; rev:3; metadata:attack_target Client_Endpoint, created_at 2016_06_14, deployment Perimeter, signature_severity Major, tag Ransomware, updated_at 2020_07_15, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;)