SSL/TLS Keywords
Several rule keywords to match on various properties of the TLS/SSL handshake.
All supported fields are sticky buffers and can be used with fast_pattern
.
tls.cert_subject
Matches the TLS/SSL certificate subject field.
Example:
alert tls any any -> any any (classtype:misc-attack; \
msg:"content matching in tls subject field"; \
tls.cert_subject; content:"Test Certificate ECDSA"; sid:1; rev:1;)
tls.cert_issuer
Matches the TLS/SSL certificate issuer field.
Examples:
alert tls any any -> any any (classtype:misc-attack; \
msg:"content matching in tls issuer field"; \
tls.cert_issuer; content:"Let's Encrypt"; sid:2; rev:1;)
tls.sni
Matches the TLS/SSL server name indication field.
Example:
alert tls any any -> any any (classtype:misc-attack; \
msg:"content matching in tls sni field"; \
tls.sni; content:"example.org"; sid:3; rev:1;)
tls.certs
Does a “raw” match on each of the certificates in the TLS certificate chain.
Example:
alert tls any any -> any any (classtype:misc-attack; \
msg:"content matching Algorithm Id sha256WithRSAEncryption"; \
tls.certs; content:"|2a 86 48 86 f7 0d 01 01 0b|"; sid:4; rev:1;)