JA4 t13d1516h2_8daaf6152771_8e37aa83b3bc

t13d1516h2_8daaf6152771_8e37aa83b3bc

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

15

Extensions offered

16

ALPN

h2

Same tool, different options

These 3 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.

• t13d1616h2_46e7e9700bed_8e37aa83b3bc
• t13d1616h2_86a278354501_8e37aa83b3bc
• t13d1716h2_5b57614c22b0_8e37aa83b3bc

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 15

• TLS_AES_128_GCM_SHA256
• TLS_CHACHA20_POLY1305_SHA256
• TLS_AES_256_GCM_SHA384
• TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
• TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
• TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
• TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
• TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
• TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
• TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
• TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
• TLS_RSA_WITH_AES_128_GCM_SHA256
• TLS_RSA_WITH_AES_256_GCM_SHA384
• TLS_RSA_WITH_AES_128_CBC_SHA
• TLS_RSA_WITH_AES_256_CBC_SHA

Extensions 16

• server_name
• extended_master_secret
• renegotiation_info
• supported_groups
• ec_point_formats
• session_ticket
• application_layer_protocol_negotiation
• status_request
• 34 (0x0022)
• signed_certificate_timestamp
• key_share
• supported_versions
• signature_algorithms
• psk_key_exchange_modes
• record_size_limit
• encrypted_client_hello

Named groups 5

• SecP256r1MLKEM768
• x25519
• secp256r1
• secp384r1
• secp521r1

Point formats 1

• uncompressed

771,4865-4867-4866-49195-49199-52393-52392-49196-49200-49171-49172-156-157-47-53,0-23-65281-10-11-35-16-5-34-18-51-43-13-45-28-65037,4588-29-23-24-25,0

Seen in live traffic

Connections

204

First seen

2026-08-23 23:21 UTC

Last seen

2026-10-08 04:11 UTC

Transport

TCP

JA3 hashes absorbed

4

The same client, 4 different JA3s

This one JA4 covers 4 distinct JA3 hashes. A JA3 hashes the cipher and extension lists in the order they arrived, so a client that shuffles them — which Chrome and its derivatives do on purpose — produces a new JA3 almost every connection and fragments into what looks like 4 unrelated clients. JA4 sorts those lists before hashing, which is why all of it lands here instead.

• d4db205a0e09a5483ae292af1424960f
• e5e6f8c2d91420315471d8db1c9fe55d
• 81b9ecf7788a9f3a6f081d3d9337e77f
• dd333e8c5db515491bfa87b75be35fdd

User-Agents seen on this fingerprint

• Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:156.0) Gecko/20100101 Firefox/156.0 379×
• Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:155.0) Gecko/20100101 Firefox/155.0 270×
• Mozilla/5.0 (X11; Linux x86_64; rv:156.0) Gecko/20100101 Firefox/156.0 266×
• Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:157.0) Gecko/20100101 Firefox/157.0 73×
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:156.0) Gecko/20100101 Firefox/156.0 59×
• Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:154.0) Gecko/20100101 Firefox/154.0 48×
• Mozilla/5.0 (X11; Linux x86_64; rv:155.0) Gecko/20100101 Firefox/155.0 11×
• Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:154.0) Gecko/20100101 Firefox/154.0 3×

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.