8.17. JA3/JA4 Keywords

Suricata comes with JA3 (https://github.com/salesforce/ja3) and JA4 (https://github.com/FoxIO-LLC/ja4) integration. JA3 and JA4 are used to fingerprint TLS and QUIC clients.

Support must be enabled in the Suricata config file (set app-layer.protocols.tls.ja{3,4}-fingerprints to yes). If it is not explicitly disabled (no) , it will be enabled if a loaded rule requires it. Note that JA3/JA4 support can also be disabled at compile time; it is possible to use the requires: feature ja{3,4}; keyword to skip rules if no JA3/JA4 support is present.

8.17.1. ja3.hash

Match on JA3 hash (md5).

Example:

alert tls any any -> any any (msg:"match JA3 hash"; \
    ja3.hash; content:"e7eca2baf4458d095b7f45da28c16c34"; \
    sid:100001;)

ja3.hash is a 'sticky buffer'.

ja3.hash can be used as fast_pattern.

ja3.hash replaces the previous keyword name: ja3_hash. You may continue to use the previous name, but it's recommended that rules be converted to use the new name.

8.17.2. ja3.string

Match on JA3 string.

Example:

alert tls any any -> any any (msg:"match JA3 string"; \
    ja3.string; content:"19-20-21-22"; \
    sid:100002;)

ja3.string is a 'sticky buffer'.

ja3.string can be used as fast_pattern.

ja3.string replaces the previous keyword name: ja3_string. You may continue to use the previous name, but it's recommended that rules be converted to use the new name.

8.17.3. ja3s.hash

Match on JA3S hash (md5).

Example:

alert tls any any -> any any (msg:"match JA3S hash"; \
    ja3s.hash; content:"b26c652e0a402a24b5ca2a660e84f9d5"; \
    sid:100003;)

ja3s.hash is a 'sticky buffer'.

ja3s.hash can be used as fast_pattern.

8.17.4. ja3s.string

Match on JA3S string.

Example:

alert tls any any -> any any (msg:"match on JA3S string"; \
    ja3s.string; content:"771,23-35"; sid:100004;)

ja3s.string is a 'sticky buffer'.

ja3s.string can be used as fast_pattern.

8.17.5. ja4.hash

Match on JA4 hash (e.g. q13d0310h3_55b375c5d22e_cd85d2d88918).

Example:

alert quic any any -> any any (msg:"match JA4 hash"; \
    ja4.hash; content:"q13d0310h3_55b375c5d22e_cd85d2d88918"; \
    sid:100001;)

ja4.hash is a 'sticky buffer'.

ja4.hash can be used as fast_pattern.