ET HUNTING ZIP file download over raw TCP

Query · suricata

flow:established,to_client;
stream_size:client,<,5;
dsize:>11;
content:"PK|03 04|"; fast_pattern; startswith;
byte_test:1,<=,20,0,relative;
Raw source ET HUNTING ZIP file download over raw TCP · 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 tcp $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET HUNTING ZIP file download over raw TCP";
    flow:established,to_client;
    stream_size:client,<,5;
    dsize:>11;
    content:"PK|03 04|"; fast_pattern; startswith;
    byte_test:1,<=,20,0,relative;
    reference:url,users.cs.jmu.edu/buchhofp/forensics/formats/pkzip.html;
    classtype:misc-activity;
    sid:2035482; rev:1;
    metadata:attack_target Client_Endpoint, created_at 2022_03_16, deployment Perimeter, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_03_16;
)

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