ET MALWARE Suspected Brute Ratel CnC Activity (POST)

Query · suricata

flow:established,to_server;
http.method;
content:"POST";
http.uri;
content:!"?";
content:!"=";
http.header_names; bsize:53;
content:"|0d 0a|User-Agent|0d 0a|Host|0d 0a|Content-Length|0d 0a|Cache-Control|0d 0a 0d 0a|"; fast_pattern;
http.host;
content:!".opera.com"; endswith;
http.user_agent;
content:!"MSIE";
content:!"Mozilla/4.";
http.request_body;
pcre:"/^[A-Za-z0-9=+/\x22\x00]{100,1000}$/";
Raw source ET MALWARE Suspected Brute Ratel CnC Activity (POST) · 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 -> $EXTERNAL_NET any (
    msg:"ET MALWARE Suspected Brute Ratel CnC Activity (POST)";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:!"?";
    content:!"=";
    http.header_names; bsize:53;
    content:"|0d 0a|User-Agent|0d 0a|Host|0d 0a|Content-Length|0d 0a|Cache-Control|0d 0a 0d 0a|"; fast_pattern;
    http.host;
    content:!".opera.com"; endswith;
    http.user_agent;
    content:!"MSIE";
    content:!"Mozilla/4.";
    http.request_body;
    pcre:"/^[A-Za-z0-9=+/\x22\x00]{100,1000}$/";
    reference:url,unit42.paloaltonetworks.com/brute-ratel-c4-tool/;
    reference:md5,1b97637fd83abfb7ecab040a4cda2d52;
    reference:md5,35c16888bdda9dd254a978d3a7c9814e;
    reference:md5,40afe8c95a3517ad07d3700ad46c2664;
    reference:md5,229648443814814cde5f01bf0f577e29;
    reference:md5,35c16888bdda9dd254a978d3a7c9814e;
    classtype:command-and-control;
    sid:2037711; rev:2;
    metadata:attack_target Client_Endpoint, created_at 2022_07_07, deployment Perimeter, performance_impact Moderate, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_05_20;
)

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