ET WEB_CLIENT Great Cannon DDoS JS M4

Query · suricata

flow:established,to_client;
http.stat_code;
content:"200";
file.data;
content:"var _a|3d 22|"; depth:8;
content:"|22 2c|_b|3d 22|"; within:120;
content:"|22 2c|_c|3d 22|"; within:120;
content:"|22 3b|eval|28|function|28 5f 2c|"; within:120;
content:"|29 7b|if|28|n|3d|function|28 5f 29 7b|return|28 5f|"; distance:9; within:27; fast_pattern;
Raw source ET WEB_CLIENT Great Cannon DDoS JS M4 · Suricata
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Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET WEB_CLIENT Great Cannon DDoS JS M4";
    flow:established,to_client;
    http.stat_code;
    content:"200";
    file.data;
    content:"var _a|3d 22|"; depth:8;
    content:"|22 2c|_b|3d 22|"; within:120;
    content:"|22 2c|_c|3d 22|"; within:120;
    content:"|22 3b|eval|28|function|28 5f 2c|"; within:120;
    content:"|29 7b|if|28|n|3d|function|28 5f 29 7b|return|28 5f|"; distance:9; within:27; fast_pattern;
    reference:url,citizenlab.ca/2015/04/chinas-great-cannon/;
    reference:url,twitter.com/chrisdoman/status/1168576334777454594;
    classtype:attempted-dos;
    sid:2027964; rev:4;
    metadata:affected_product Web_Browsers, attack_target Client_Endpoint, created_at 2019_09_06, deployment Perimeter, signature_severity Minor, updated_at 2020_11_19;
)

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