ET MALWARE Win32/Ketrican CnC Activity

Query · suricata

flow:to_server,established;
http.method;
content:"POST";
http.uri;
content:".aspx?a1="; fast_pattern;
pcre:"/^[a-f0-9]{8}$/R";
http.request_body;
content:"AA"; depth:2;
pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/";
http.content_len;
content:"88";
Raw source ET MALWARE Win32/Ketrican 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 -> $EXTERNAL_NET any (
    msg:"ET MALWARE Win32/Ketrican CnC Activity";
    flow:to_server,established;
    http.method;
    content:"POST";
    http.uri;
    content:".aspx?a1="; fast_pattern;
    pcre:"/^[a-f0-9]{8}$/R";
    http.request_body;
    content:"AA"; depth:2;
    pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/";
    http.content_len;
    content:"88";
    reference:url,www.welivesecurity.com/wp-content/uploads/2019/07/ESET_Okrum_and_Ketrican.pdf;
    reference:md5,e46d8f510c09f09e2e6b958b84190d8b;
    reference:md5,03a2f5ea0cea83e77770a4018c4469ab;
    classtype:command-and-control;
    sid:2027728; rev:3;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_07_18, deployment Perimeter, deployment SSLDecrypt, malware_family Win32_Ketrican, confidence High, signature_severity Major, tag Ketrican, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_31;
)

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