Rule History

alert tls $EXTERNAL_NET [443,4443] -> $HOME_NET any (msg:"ET MALWARE Possible Dyre SSL Cert M1 (L O)"; flow:established,to_client; tls.cert_serial; content:"00:"; startswith; bsize:26; tls.certs; content:"|06 03 55 04 06 13 02|"; pcre:"/^[A-Z]{2}[01]/R"; content:"|30 09 06 03 55 04 08 0c 02|"; distance:1; within:9; fast_pattern; pcre:"/^[A-Z]{2}[01]/R"; content:"|06 03 55 04 07 0c|"; within:9; byte_test:1,>,9,0,relative; byte_test:1,<,121,0,relative; pcre:"/^.{1}(?=[a-z0-9]{0,119}[A-Z])(?=[A-Z0-9]{0,119}[a-z])[a-zA-Z0-9]{10,120}[01]/R"; content:"|06 03 55 04 0a 0c|"; within:9; byte_extract:1,0,orglen,relative; content:!"|20|"; within:orglen; pcre:"/^(?=[a-z0-9]{0,119}[A-Z])(?=[A-Z0-9]{0,119}[a-z])[a-zA-Z0-9]{10,120}[01]/R"; content:"|06 03 55 04 03 0c|"; within:9; byte_extract:1,0,cnlen,relative; content:!"|2e|"; within:cnlen; content:!"|2a|"; within:cnlen; pcre:"/^(?P<var>[a-zA-Z0-9]{1,120}[01]).+?\x55\x04\x03.{2}(?P=var)/Rs"; classtype:trojan-activity; sid:2021432; rev:5; metadata:attack_target Client_Endpoint, created_at 2015_07_17, deployment Perimeter, confidence Medium, signature_severity Major, tag SSL_Malicious_Cert, updated_at 2022_03_27;)