ET HUNTING [@Silv0123] Possible Fake Microsoft Office User-Agent Observed

Query · suricata

flow:established,to_server;
http.user_agent;
content:"Microsoft Office"; startswith; fast_pattern;
pcre:"/^[^\x3b\x2f\x28]+$/R";
content:!"2014"; endswith;
content:!"Discovery"; endswith;
content:!"OneNote"; endswith;
Raw source ET HUNTING [@Silv0123] Possible Fake Microsoft Office User-Agent Observed · 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 -> $EXTERNAL_NET any (
    msg:"ET HUNTING [@Silv0123] Possible Fake Microsoft Office User-Agent Observed";
    flow:established,to_server;
    http.user_agent;
    content:"Microsoft Office"; startswith; fast_pattern;
    pcre:"/^[^\x3b\x2f\x28]+$/R";
    content:!"2014"; endswith;
    content:!"Discovery"; endswith;
    content:!"OneNote"; endswith;
    reference:url,twitter.com/silv0123/status/1437869745961832455;
    classtype:bad-unknown;
    sid:2033960; rev:3;
    metadata:created_at 2021_09_16, confidence Medium, signature_severity Minor, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_10_25;
)

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