ET MALWARE CNRarypt Ransomware CnC Activity

Query · suricata

flow:established,to_server;
http.method;
content:"GET";
http.uri;
content:"/HOW_TO_BACK_YOUR_FILES.txt"; endswith; fast_pattern;
http.user_agent;
content:"CertUtil URL Agent"; bsize:18;
http.header_names;
content:!"Referer";
Raw source ET MALWARE CNRarypt Ransomware CnC Activity · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE CNRarypt Ransomware CnC Activity";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/HOW_TO_BACK_YOUR_FILES.txt"; endswith; fast_pattern;
    http.user_agent;
    content:"CertUtil URL Agent"; bsize:18;
    http.header_names;
    content:!"Referer";
    reference:md5,62292df897bf304872aad2dc92c96d70;
    classtype:trojan-activity;
    sid:2033075; rev:1;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_06_03, deployment Perimeter, confidence High, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_06_03, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;
)

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