JA4 Fingerprint Directory

t13d041000_16476d049b0b_17bacd9b6122

Firefox — inferred from the User-Agent on its requests.

What this fingerprint encodes

Transport

TCP

TLS version

TLS 1.3

Server name

server name sent

Cipher suites offered

4

Extensions offered

10

ALPN

none offered

Same tool, different options

These 1 other fingerprints share this one's JA4_c — the extension and signature-algorithm hash. A client that keeps its extension set constant while varying its cipher list produces exactly this pattern, which is what a scanner iterating cipher suites looks like. A JA3 cannot show you this: its single MD5 collapses ciphers and extensions together, so every variation looks like an unrelated client.

• t13d061000_a150a9413979_17bacd9b6122

The hello it was computed from

Recovered because the proxy now stores the pre-hash JA3 string alongside the digest. Every number below came out of this client's ClientHello; anything we cannot name in the IANA registry is shown as its raw value rather than guessed at.

Version

TLS 1.2

Cipher suites 4

• TLS_AES_256_GCM_SHA384
• TLS_CHACHA20_POLY1305_SHA256
• TLS_AES_128_GCM_SHA256
• TLS_EMPTY_RENEGOTIATION_INFO_SCSV

Extensions 10

• server_name
• ec_point_formats
• supported_groups
• session_ticket
• encrypt_then_mac
• extended_master_secret
• signature_algorithms
• supported_versions
• psk_key_exchange_modes
• key_share

Named groups 5

• x25519
• secp256r1
• x448
• secp521r1
• secp384r1

Point formats 3

• uncompressed
• ansiX962_compressed_prime
• ansiX962_compressed_char2

771,4866-4867-4865-255,0-11-10-35-22-23-13-43-45-51,29-23-30-25-24,0-1-2

Seen in live traffic

Connections

3

First seen

2026-08-23 18:31 UTC

Last seen

2026-08-23 18:31 UTC

Transport

TCP

User-Agents seen on this fingerprint

• Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0 1×

A User-Agent is self-declared and trivially forged, so this names an observation rather than proving an identity. It is still the strongest signal available: the fingerprint comes off the TLS handshake and the User-Agent off the request that followed, and one client build keeping a stable JA4 while changing what it calls itself is a finding in its own right.

This entry is an observation, not a policy decision. It is here because the edge saw it, not because anyone reviewed it, and it blocks nothing on its own. Only the curated tier drives classification and banning.