ET INFO Observed DNS over HTTPS Domain (dns4me .net) in TLS SNI

Query · suricata

flow:established,to_server;
tls.sni; bsize:15;
content:".dns4me.net"; endswith; fast_pattern;
pcre:"/^[a-z]{2}\d{2}\.dns4me\.net$/";
threshold:type both, count 1, seconds 600, track by_src;
Raw source ET INFO Observed DNS over HTTPS Domain (dns4me .net) 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 $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET INFO Observed DNS over HTTPS Domain (dns4me .net) in TLS SNI";
    flow:established,to_server;
    tls.sni; bsize:15;
    content:".dns4me.net"; endswith; fast_pattern;
    pcre:"/^[a-z]{2}\d{2}\.dns4me\.net$/";
    threshold:type both, count 1, seconds 600, track by_src;
    reference:url,github.com/curl/curl/wiki/DNS-over-HTTPS;
    classtype:misc-activity;
    sid:2052673; rev:3;
    metadata:created_at 2024_05_16, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, tag DNS_over_HTTPS, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_12_01, reviewed_at 2024_10_04, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1572, mitre_technique_name Protocol_Tunneling;
)

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