Versions (3)
Version DetailsCurrent
Rev: 4 • Apr 19, 2017, 12:00 PMET PHISHING Lets Encrypt Free SSL Cert Observed with IDN/Punycode Domain - Possible Phishing
alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET PHISHING Lets Encrypt Free SSL Cert Observed with IDN/Punycode Domain - Possible Phishing"; flow:established,from_server; tls.cert_subject; content:"xn--"; tls.cert_issuer; content:"O=Let's Encrypt"; reference:url,isc.sans.edu/forums/diary/Tool+to+Detect+Active+Phishing+Attacks+Using+Unicode+LookAlike+Domains/22310/; reference:url,letsencrypt.org/about/; classtype:policy-violation; sid:2024227; rev:4; metadata:affected_product Web_Browsers, attack_target Client_Endpoint, created_at 2017_04_19, deployment Perimeter, confidence Medium, signature_severity Critical, tag Phishing, updated_at 2020_08_20, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1566, mitre_technique_name Phishing;)
Apr 19, 2017, 12:00 PM
Aug 20, 2020, 12:00 PM
Sep 21, 2024, 3:00 AM
May 30, 2025, 12:04 AM
rules/emerging-phishing.rules