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SID: 2025320 • Source: et/open

Versions (5)

Version DetailsCurrent

Rev: 4Feb 6, 2018, 12:00 PM

ET POLICY [Fidelis] Abnormal Very Long x509v3 SubjectKeyIdentifier Extension

alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET POLICY [Fidelis] Abnormal Very Long x509v3 SubjectKeyIdentifier Extension"; flow:established,to_client; dsize:>768; content:"|16 03|"; depth:2; content:"|06 03 55 1d 0e 04|"; offset:336; pcre:"/^[\x80-\xff]/R"; threshold:type limit, track by_src, seconds 30, count 1; reference:url,www.fidelissecurity.com/threatgeek/2018/02/exposing-x509-vulnerabilities; classtype:misc-attack; sid:2025320; rev:4; metadata:attack_target Client_Endpoint, created_at 2018_02_06, deployment Perimeter, performance_impact Significant, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_23;)

Feb 6, 2018, 12:00 PM

Apr 23, 2024, 12:00 PM

Sep 21, 2024, 3:00 AM

Sep 29, 2025, 9:34 PM

rules/emerging-policy.rules