TLS ClientHello (JA4)

t13d1516h2_8daaf6152771_14f25f0c9e96

first seen 2026-10-05 18:37 · last seen 2026-10-30 23:51 · JSON

Inconsistencies

User-Agents observed with this fingerprint that contradict what it proves at the wire. all inconsistencies →

fingerprint User-Agent claims wire shows confidence seen first seen last seen

t13d1516h2_8daaf6152771_14f25f0c9e96

Mozilla/5.0 (X11; Linux x86_64; rv:157.0) Gecko/…

User-Agent claims Firefox 157.0

TLS extensions or signature algorithms differ from every measured Firefox capture

The cipher suites match Firefox, but the extension set or signature algorithms differ from every capture even after normalizing handshake-variant extensions. Most likely a field-trial, ECH, or build variant the catalog has not captured; occasionally mimicry. This sharpens as catalog coverage grows.

Full User-Agent	Mozilla/5.0 (X11; Linux x86_64; rv:157.0) Gecko/20100101 Firefox/157.0
Claimed version	157.0
Measured versions	146.0.1, 154.0, 140.0.2, 157.0.1, 151.0.2, 155.0, 153.0.3, 142.0.1, 153.0.4, 152.0.6, 150.0.2, 135.0, 156.0.1, 132.0, 152.0.3, 141.0, 153.0, 151.0.3, 156.0, 152.0.4, 151.0, 152.0.1, 151.0.4, 139.0, 153.0.1, 158.0.1, 152.0.5, 157.0, 158.0, 148.0.2, 137.0, 155.0.1, 144.0.2, 154.0.1, 134.0
Layer	cipher suites match; extension set or signature algorithms differ
JA4 label	unlabeled

low

2026-10-05

2026-10-10

t13d1516h2_8daaf6152771_14f25f0c9e96

Mozilla/5.0 (X11; Linux x86_64; rv:158.0) Gecko/…

User-Agent claims Firefox 158.0

TLS extensions or signature algorithms differ from every measured Firefox capture

Full User-Agent	Mozilla/5.0 (X11; Linux x86_64; rv:158.0) Gecko/20100101 Firefox/158.0
Claimed version	158.0
Measured versions	146.0.1, 154.0, 140.0.2, 157.0.1, 151.0.2, 155.0, 153.0.3, 142.0.1, 153.0.4, 152.0.6, 150.0.2, 135.0, 156.0.1, 132.0, 152.0.3, 141.0, 153.0, 151.0.3, 156.0, 152.0.4, 151.0, 152.0.1, 151.0.4, 139.0, 153.0.1, 158.0.1, 152.0.5, 157.0, 158.0, 148.0.2, 137.0, 155.0.1, 144.0.2, 154.0.1, 134.0
Layer	cipher suites match; extension set or signature algorithms differ
JA4 label	unlabeled

low

2026-10-20

2026-10-30

Last 7 days (4 observations)

Distinct clients per day (last 30 days, peak 2/day)

Distinct clients are counted by IP-hash per complete UTC day — unlike observation counts this is insensitive to one chatty client, but NAT merges clients and address rotation splits them.

Decomposed attributes

Protocol	`t (TLS over TCP)`
TLS version	`13`
SNI	`d (domain)`
Cipher count	`15`
Extension count	`16`
ALPN	`h2`
Ciphers	`002f, 0035, 009c, 009d, 1301, 1302, 1303, c013, c014, c02b, c02c, c02f, c030, cca8, cca9`
Extensions	`0005, 000a, 000b, 000d, 0012, 0017, 001c, 0022, 0023, 002b, 002d, 0033, fe0d, ff01`
Signature algorithms	`0403, 0503, 0603, 0804, 0805, 0806, 0401, 0501, 0601, 0203, 0201, 0904, 0905, 0906`
JA4_r	`t13d1516h2_002f,0035,009c,009d,1301,1302,1303,c013,c014,c02b,c02c,c02f,c030,cca8,cca9_0005,000a,000b,000d,0012,0017,001c,0022,0023,002b,002d,0033,fe0d,ff01_0403,0503,0603,0804,0805,0806,0401,0501,0601,0203,0201,0904,0905,0906`
JA4_o (sample)	`t13d1516h2_77608d807651_ed7b5f4f09a9`
JA4_ro (sample)	`t13d1516h2_1301,1303,1302,c02b,c02f,cca9,cca8,c02c,c030,c013,c014,009c,009d,002f,0035_0000,0017,ff01,000a,000b,0023,0010,0005,0022,0012,0033,002b,000d,002d,001c,fe0d_0403,0503,0603,0804,0805,0806,0401,0501,0601,0203,0201,0904,0905,0906`

Co-observed signals

Signals from other families seen in the same observation. A fingerprint spread thinly across many lower-layer signatures is a classic inconsistency signal.

HTTP request (JA4H)

fingerprint	co-occurrences
`ge20nr11enus_187a9385d229_000000000000_000000000000`	9
`ge20nn12enus_a72b71f519fc_000000000000_000000000000`	1
`ge20nn10enus_d353d425b0bb_000000000000_000000000000` Match?Exact match in Thumbprint's published controlled catalog captures: firefox 152.0.1.The fingerprint page shows the full measured match list. More on the catalog.	1
`ge20nn10enus_b3034183f430_000000000000_000000000000`	1
`ge20nr13enus_44e1f6d71293_000000000000_000000000000`	1

HTTP/2 frames (Akamai)

fingerprint	co-occurrences
`1:65536;2:0;4:131072;5:16384\|12517377\|3:0:0:22\|m,p,a,s` Match?Exact match in Thumbprint's published controlled catalog captures: firefox 153.0, firefox 153.0.3, firefox 155.0.1, +31 more.The fingerprint page shows the full measured match list. More on the catalog.	11
`1:65536;2:0;4:131072;5:16384\|12517377\|3:0:0:42\|m,p,a,s` Match?Exact match in Thumbprint's published controlled catalog captures: firefox 154.0, firefox 152.0.5, firefox 152.0.1, +3 more.The fingerprint page shows the full measured match list. More on the catalog.	2

TCP SYN (p0f)

fingerprint	co-occurrences
`4:40+24:0:1380:mss*47,10:mss,sok,ts,nop,ws:df,id+:0`	4
`4:39+25:0:1380:mss*47,10:mss,sok,ts,nop,ws:df,id+:0`	3
`4:53+11:0:1380:mss*47,10:mss,sok,ts,nop,ws:df,id+:0`	2
`4:44+20:0:1412:mss*44,10:mss,sok,ts,nop,ws:df,id+:0`	2
`4:47+17:0:1420:mss*46,10:mss,sok,ts,nop,ws:df,id+:0`	2

TCP SYN (JA4T)

fingerprint	co-occurrences
`64860_2-4-8-1-3_1380_10`	9
`65320_2-4-8-1-3_1420_10`	2
`64240_2-4-8-1-3_1412_10`	2

User-Agent

fingerprint	co-occurrences
`Mozilla/5.0 (X11; Linux x86_64; rv:157.0) Gecko/20100101 Firefox/157.0`	6
`Mozilla/5.0 (X11; Linux x86_64; rv:158.0) Gecko/20100101 Firefox/158.0`	5
`Mozilla/5.0 (X11; Linux x86_64; rv:159.0) Gecko/20100101 Firefox/159.0`	2

Country

fingerprint	co-occurrences
`PL` · Poland	7
`US` · United States	2
`UA` · Ukraine	2
`IT` · Italy	2

Network (ASN)

fingerprint	co-occurrences
`AS16276` · OVH SAS	7
`AS11878` · tzulo, inc.	2
`AS12874` · Fastweb SpA	2
`AS34700` · MAXNET TELECOM, LTD	2

TLS supported groups

fingerprint	co-occurrences
`11ec,001d,0017,0018,0019,0202`	7

Cross-transport links

TLS ClientHello fingerprints observed from the same client via the beacon's correlation id on the other transport (e.g. this stack over TCP ↔ that stack over QUIC).

fingerprint	linked observations
`q13d0315h3_55b375c5d22e_bb76f32061e3`	10