ET HUNTING ZIP file exfiltration over raw TCP

Query · suricata

flow:established,to_server;
stream_size:server,<,5;
dsize:>11;
content:"PK|03 04|"; fast_pattern; startswith;
byte_test:1,<=,20,0,relative;
content:"|00 00 00|"; distance:1; within:3;
Raw source ET HUNTING ZIP file exfiltration over raw TCP · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert tcp $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET HUNTING ZIP file exfiltration over raw TCP";
    flow:established,to_server;
    stream_size:server,<,5;
    dsize:>11;
    content:"PK|03 04|"; fast_pattern; startswith;
    byte_test:1,<=,20,0,relative;
    content:"|00 00 00|"; distance:1; within:3;
    reference:url,users.cs.jmu.edu/buchhofp/forensics/formats/pkzip.html;
    classtype:misc-activity;
    sid:2035478; rev:2;
    metadata:attack_target Client_Endpoint, created_at 2022_03_16, deployment Perimeter, performance_impact Moderate, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_03_16;
)

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