ET INFO Cloudflare DNS Over HTTPS Certificate Inbound

Query · suricata

flow:established,to_client;
threshold:type limit, track by_src, count 1, seconds 300;
tls.cert_subject;
content:"C=US, ST=California, L=San Francisco, O=Cloudflare, Inc., CN=cloudflare-dns.com"; endswith; fast_pattern;
Raw source ET INFO Cloudflare DNS Over HTTPS Certificate Inbound · 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 Cloudflare DNS Over HTTPS Certificate Inbound";
    flow:established,to_client;
    threshold:type limit, track by_src, count 1, seconds 300;
    tls.cert_subject;
    content:"C=US, ST=California, L=San Francisco, O=Cloudflare, Inc., CN=cloudflare-dns.com"; endswith; fast_pattern;
    reference:url,developers.cloudflare.com/1.1.1.1/dns-over-https/request-structure/;
    classtype:misc-activity;
    sid:2027671; rev:5;
    metadata:created_at 2019_07_03, confidence Medium, signature_severity Informational, tag DoH, updated_at 2020_09_17;
)

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