ET INFO URL Shortener (s .yam .com) in TLS SNI

Query · suricata

flow:established,to_client;
tls.cert_subject;
content:"s.yam.com"; fast_pattern;
pcre:"/CN=(?:[^\r\n]+?\.)?s\.yam\.com(?!\.)/";
Raw source ET INFO URL Shortener (s .yam .com) in TLS SNI · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert tls $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET INFO URL Shortener (s .yam .com) in TLS SNI";
    flow:established,to_client;
    tls.cert_subject;
    content:"s.yam.com"; fast_pattern;
    pcre:"/CN=(?:[^\r\n]+?\.)?s\.yam\.com(?!\.)/";
    classtype:misc-activity;
    sid:2045632; rev:1;
    metadata:attack_target Client_Endpoint, created_at 2023_05_10, deployment Perimeter, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_05_10;
)

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