alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE [eSentire] Win32/GandCrab v4/5 Ransomware CnC Activity"; flow:established,to_server; threshold:type limit, count 1, seconds 60, track by_src; http.method; content:"POST"; http.uri; pcre:"/\.(?:bmp|png|gif|jpg)$/"; http.user_agent; content:"Mozilla/5.0 (Windows NT 6.1|3b 20|WOW64"; http.request_body; content:"wfKD6iudumBkmp"; depth:14; fast_pattern; pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/si"; http.content_type; content:"multipart/form-data"; startswith; http.header_names; content:!"Referer"; content:!"Accept"; classtype:command-and-control; sid:2025638; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_07_04, deployment Perimeter, malware_family GandCrab, confidence High, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_25, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;)