ET HUNTING Terse Unencrypted Request for Google - Likely Connectivity Check

Query · suricata

flow:established,to_server;
http.request_line;
content:"GET / "; startswith;
http.host; dotprefix;
content:".google.com"; fast_pattern;
http.header_names;
content:!"|0d 0a|Referer|0d 0a|";
content:!"|0d 0a|User-Agent|0d 0a|";
content:!"|0d 0a|Accept";
Raw source ET HUNTING Terse Unencrypted Request for Google - Likely Connectivity Check · 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 80 (
    msg:"ET HUNTING Terse Unencrypted Request for Google - Likely Connectivity Check";
    flow:established,to_server;
    http.request_line;
    content:"GET / "; startswith;
    http.host; dotprefix;
    content:".google.com"; fast_pattern;
    http.header_names;
    content:!"|0d 0a|Referer|0d 0a|";
    content:!"|0d 0a|User-Agent|0d 0a|";
    content:!"|0d 0a|Accept";
    reference:md5,7ca63bab6e05704d2c7b48461e563f4c;
    classtype:trojan-activity;
    sid:2036303; rev:2;
    metadata:created_at 2022_04_22, performance_impact Moderate, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_04_22;
)

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