ET POLICY Windows 3.1 User-Agent Detected - Possible Malware or Non-Updated System

Query · suricata

flow:established,to_server;
http.user_agent;
content:"Windows 3.1"; fast_pattern;
content:!"Cisco AnyConnect VPN Agent";
Raw source ET POLICY Windows 3.1 User-Agent Detected - Possible Malware or Non-Updated System · 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 http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET POLICY Windows 3.1 User-Agent Detected - Possible Malware or Non-Updated System";
    flow:established,to_server;
    http.user_agent;
    content:"Windows 3.1"; fast_pattern;
    content:!"Cisco AnyConnect VPN Agent";
    classtype:policy-violation;
    sid:2011694; rev:11;
    metadata:created_at 2010_07_30, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_13;
)

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