ET MALWARE CORESHELL Malware Response from server

Query · suricata

flow:from_server,established;
file_data;
content:"O|00|K|00 00 00|"; within:6;
pcre:"/^(?:(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4}))?$/R";
Raw source ET MALWARE CORESHELL Malware Response from server · Suricata
Esc
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 -> $HOME_NET any (
    msg:"ET MALWARE CORESHELL Malware Response from server";
    flow:from_server,established;
    file_data;
    content:"O|00|K|00 00 00|"; within:6;
    pcre:"/^(?:(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4}))?$/R";
    reference:url,www.fireeye.com/resources/pdfs/apt28.pdf;
    classtype:trojan-activity;
    sid:2019584; rev:3;
    metadata:created_at 2014_10_29, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;
)

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