TLS Fingerprint основная проблема BAS

[clarabellerising]

@rsgmsk hahah, odinakoviy tls otpechatok palevo, smeshno, delo v authentichnosti TLS browsera, a ne ego unikalnogo tls, esli tls ja3(kotoriy mojet randomitsa v novih versiah izza random tls extension) ja4 autentichen browser'y znachit eto browser, a esli ego hash autentichen curl/axios/blablabla znachit eto bot, i delo voobshe ne v unikalnosti
Vam uje skazali reshenie, ne ispolzuyte firefox, current browser version fingerprint = bas version => profit, vse ne nado izobretat velosiped, hotite firefox/unikalniy TLS blablabla delayte svoe reshenie

[clarabellerising]

A to tak voznikaet oshushenie chto vi voobse ne oduplyaete chto takoe TLS fingerprint, nujno randomit prosto dlya unikalnosti, potomuchto kajdiy polzovatel doljen bit unikalen, a i kstati... a kak naschet passive os fingerprint? etot vopros vas ne zabotit?

[ranjeet]

I worked hard for about 3 months and built my own system, from proxy to everything, but I could not do it.

Because

⭐ WHY "NO PROXY IN THE WORLD" CAN MATCH CHROME’S EXACT JA3 + TCP/IP + QUIC SIGNATURE

⚠️ Short answer:
Because Chrome’s JA3, TCP stack, QUIC engine, TLS extensions, packet timings, congestion control, and OS-level fingerprints all depend on deep system-level behavior.
These things cannot be fully mimicked by a proxy because:

👉 A proxy does not replace the browser — it only forwards requests.

👉 The browser’s TCP/TLS/QUIC handshake signals are generated by the client machine.

👉 A proxy can only modify the server-side handshake (the connection between proxy and server), not the client-side handshake (the connection between browser and proxy).

Below is a deeper breakdown 👇

🔥 1. JA3 fingerprint = the browser’s TLS ClientHello

A JA3 fingerprint is built from the TLS ClientHello and includes:

Chrome’s internal TLS library

Chrome’s version-specific cipher ordering

Chrome’s supported groups (elliptic curves)

Chrome’s GREASE values/extensions

Chrome’s signature algorithms

Chrome’s ALPN list (http/1.1, h2, h3)

The extension ordering and randomness that Chrome uses

All of these are hard-coded and/or dynamically set inside Chrome.

Why a proxy fails to mimic the client JA3:
A proxy cannot replace the browser’s ClientHello. Instead, the proxy will create a new TLS handshake to the target server. That handshake is the proxy’s JA3, not the browser’s. The server can observe:

ClientHello #1: Client → Proxy (original)

ClientHello #2: Proxy → Server (spoofed)

This mismatch is detectable by server-side ML/heuristics and is a strong bot signal.

🔥 2. Chrome’s TCP/IP stack fingerprint

TCP/IP fingerprints arise from OS/network stack behavior, including:

Initial window size

TCP timestamps

TTL (Time To Live)

Retransmission behavior and intervals

Congestion control algorithm (e.g., BBR, CUBIC)

Packet pacing and ACK timing

MTU discovery behavior

Zero-window probes

OS kernel networking quirks (Linux vs Windows vs macOS)

These characteristics originate on the client machine — NOT on the proxy. A proxy cannot rewrite your OS-level TCP behavior (except by extreme kernel-level MITM modifications). Servers can use those signals to detect that a request didn’t come from a normal Chrome/TCP stack.

🔥 3. QUIC fingerprinting (HTTP/3) = IMPOSSIBLE to fully spoof

Chrome uses its own QUIC stack (cronet) with:

Version-specific QUIC crypto parameters

qlog-like packet sequencing and timing

QUIC packet pacing and loss-recovery behavior

ACK delay strategies

QPACK encoder/decoder behavior

Each Chrome version has a characteristic QUIC signature. A proxy cannot fake the browser’s end-to-end QUIC behavior because QUIC is encrypted end-to-end and tightly integrated with the client implementation. A proxy would either need to terminate and re-establish QUIC (producing a different signature) or force the connection to downgrade to HTTP/1.1 — both of which are detectable.

Common detection behavior:

Real Chrome → speaks QUIC (HTTP/3)

Bot/proxy → falls back to HTTP/1.1 or shows inconsistent QUIC behavior

🔥 4. Chrome’s TLS GREASE

Chromium implements GREASE (as in RFC 8701) — intentionally randomizing certain reserved values (extension ids, signature algorithms, etc.) to future-proof and prevent ossification. GREASE values are:

Random per connection and build

Version-dependent and platform-dependent

Proxies can’t reliably predict or reproduce Chrome’s GREASE behavior. Missing or incorrect GREASE patterns are a signal that the client is not a genuine Chrome build.

🔥 5. Chrome header ordering (very important)

Real Chrome emits request headers in a particular order and with expected fields (especially over HTTP/2). Example ordering (illustrative):

:authority
:method
:path
:scheme
sec-ch-ua
sec-ch-ua-mobile
sec-ch-ua-platform
upgrade-insecure-requests
user-agent
accept
sec-fetch-site
sec-fetch-mode
sec-fetch-user
sec-fetch-dest
accept-encoding
accept-language

Proxies commonly:

❌ Change header order

❌ Add or remove encodings

❌ Inject proxy-specific headers

❌ Re-chunk or alter HTTP/2 frames

Such differences can be used to detect non-standard clients. Even advanced antidetect browsers sometimes fail to perfectly match header framing and ordering.

🔥 6. Chrome’s OS-level artifacts

A real browser request carries many environment-dependent artifacts that a proxy cannot emulate:

Platform-dependent behavior and heuristics

Built-in compression/windowing patterns

HTTP/2 frame pacing and stream behaviors

Huffman encoding usage patterns in headers

Per-build TLS randomization nuances

A proxy cannot reproduce these low-level, OS/timing/implementation artifacts originating from the client runtime.

[sergerdn]

@ranjeet

Take ChatGPT with a grain of salt and use your own head. The stuff above is only half right.

[ranjeet]

i am used chatgpt only for typing becuse my english is not good

[ranjeet]

@sergerdn
i am not chromium devloper me be some deatils will wrong becuse i am using ai for research only i am tried to under stand how chromium genrating tsl fb.
i am 4mohtn after devloped my won proxy network with tsl spoofing but my account are still banning i am using total humen for page visit and do task

[Int64]

@rsgmsk said in TLS Fingerprint основная проблема BAS:

TLS отпечаток он разный у людей

@rsgmsk said in TLS Fingerprint основная проблема BAS:

одинаковый tls отпечаток это палево

Не путай теплое с мягким:

• настройки HTTP-клиента браузера (TLS-отпечаток, порядок расширений, заголовки)
• JS/device-fingerprint (canvas, WebGL, шрифты и т.д.)

Представь что TLS-отпечаток - это как SHA256(версия браузера/приложения/User-Agent).
Одинаковый TLS-отпечаток говорит, что клиент ведёт себя как оригинальная версия браузера/приложения и не конфликтует например с User-Agent

[Int64]

@ranjeet said in TLS Fingerprint основная проблема BAS:

but I could not do it

And all this time, my finished module was already on the forum))

https://community.bablosoft.com/topic/30528/http-client-curl-impersonate-http-2-tls-1-3-browser_presets-websocket

[tersinemuhendis]

@Int64 bad library.

[Int64]

@tersinemuhendis any proof?

[ranjeet]

I’ve started studying low-level networking to understand full network behavior in depth. The clear conclusion so far is that a TLS fingerprint cannot be formed solely by BAS (Chromium). TLS fingerprinting also depends on system-level OS behavior, where the browser + OS + network stack + hardware timing together create the final observable fingerprint.

In this process, the protocol-level fingerprint (from Chrome/Chromium) stays consistent, but OS-level packet timing, TCP implementation, congestion control, jitter, and data buffering influence the actual TLS identity.

I do see one possible direction — but this would require building a larger ecosystem where the proxy environment can either emulate or preserve OS-level network characteristics. That’s ongoing R&D, and we’ll see how it evolves.

At least one confusion is now clearly resolved: as per my current knowledge, modifying only BAS (Chromium) to produce different realistic TLS fingerprints does not seem practically feasible unless the OS-level signals are also replicated or manipulated.

(all are translated hindi to english )

[tersinemuhendis]

@Int64 https://github.com/0x676e67/rnet good tls library.

[Int64]

@tersinemuhendis My module is the same)

[dnffl0019]

отличная информация, спасибо, ребята!

[tersinemuhendis]

@Int64 Having the same boardingssl doesn't mean you're doing the same operations, my friend. Chrome also uses boardingssl, so that doesn't mean your module works the same with Chrome.

[Int64]

@tersinemuhendis omg 😲 read the module description carefully or give me real facts

[usertrue]

@Int64 пусть изобретают свой велосипед, не трать время на них.

[sergerdn]

@usertrue said in TLS Fingerprint основная проблема BAS:

@Int64 пусть изобретают свой велосипед, не трать время на них.

//режим старпера on
Люди слишком доверяют своему мнению, если взять и проверить снаружи свою гипотезу, то будет в сразу видно что происходит.
//режим старпера off