alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/GandCrab Ransomware CnC Activity"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".php?token="; fast_pattern; pcre:"/^[0-9]{2,6}$/R"; http.request_body; content:"data="; startswith; pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/Rs"; http.content_len; byte_test:0,>,200,0,string,dec; http.header_names; to_lowercase; content:!"|0d 0a|referer|0d 0a|"; content:!"|0d 0a|accept"; content:!"cookie|0d 0a|"; reference:md5,aedf80c426fb649bb258e430a3830d85; classtype:command-and-control; sid:2025254; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_01_26, deployment Perimeter, malware_family GandCrab, confidence High, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_05_01, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;)