ET HUNTING Office User-Agent Requesting Non-Standard Filename

Query · suricata

flow:established,to_server;
urilen:>30;
http.method;
content:"GET";
http.uri;
pcre:"/\.[0-9a-z]{5}$/";
http.user_agent;
content:"|3b 20|ms-office|3b 20|"; fast_pattern;
http.header_names;
content:!"|0d 0a|Referer|0d 0a|";
target:src_ip;
Raw source ET HUNTING Office User-Agent Requesting Non-Standard Filename · 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 -> $EXTERNAL_NET any (
    msg:"ET HUNTING Office User-Agent Requesting Non-Standard Filename";
    flow:established,to_server;
    urilen:>30;
    http.method;
    content:"GET";
    http.uri;
    pcre:"/\.[0-9a-z]{5}$/";
    http.user_agent;
    content:"|3b 20|ms-office|3b 20|"; fast_pattern;
    http.header_names;
    content:!"|0d 0a|Referer|0d 0a|";
    reference:md5,de9a87a8dc9eb67b3e54c452f63b2579;
    classtype:bad-unknown;
    sid:2045290; rev:1;
    metadata:attack_target Client_Endpoint, created_at 2023_05_02, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_05_02;
    target:src_ip;
)

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