Local Arkose FunCaptcha Solver (kekeds/funcaptcha-solver)

Source: https://github.com/kekeds/funcaptcha-solver Status: Self-hosted, 100% requests-based, fully reversed BDA

What It Does

Solves Arkose Labs FunCaptcha WITHOUT using external captcha services. Uses:

Browser fingerprinting (WebGL, canvas, etc.)
BDA (Blob Data Algorithm) decryption — fully reversed
Cryptographic operations (AES-CBC, MD5 key derivation)
JavaScript execution via Node.js jsdom
TLS fingerprint impersonation via curl_cffi

Dependencies

# Python
pip install cryptography curl_cffi pycryptodome flask numpy colorama PyExecJS javascript

# Node.js (v22+)
npm install jsdom

How It Works

Flask server on port 8003
POST /funcaptcha/createTask with preset, chrome_version, optional proxy and blob
Poll /funcaptcha/getTask until status: "completed"
Returns captcha.token — the Arkose solution token

Preset System

Each site needs a preset with:

siteurl — where the Arkose iframe loads
sitekey — the Arkose public key
apiurl — the Arkose API subdomain
data.window__ancestor_origins — iframe parent chain
data.client_config__sitedata_location_href — iframe URL
data.window__tree_structure — DOM tree structure of iframe nesting
data.window__tree_index — which iframe in the tree

Built-in Presets (working)

linkedin_register
match_login
twitter_register
twitter_unlock
outlook_register
outlook_phone

GitHub Preset (added, not verified)

"github_signup": {
    "siteurl": "https://github.com/signup",
    "sitekey": "0651BCE4-8F66-4F8B-9C6D-5F5411DD9158",
    "apiurl": "https://github-api.arkoselabs.com",
    "data": {
        "window__ancestor_origins": ["https://github.com", ...],
        "client_config__sitedata_location_href": "https://github.com/signup",
        "window__tree_structure": "[[],[],[[]]]",
        "window__tree_index": [2, 0]
    }
}

Status: Solver thread crashes silently — preset may need adjustment.

Known Issues

Preset Merge Order Bug (FIXED 2026-07-09)

CRITICAL: The original code at line 1476 had a bug where user parameters were OVERRIDDEN by preset defaults:

# WRONG — preset overrides user blob
data={**data, **preset.get()[data["preset"]]}

This means even if the script captures a real blob and passes it as {"blob": "real_blob_value"}, the solver ignores it and uses the preset's "blob": "undefined". This causes "DENIED ACCESS" from Arkose because the blob is wrong.

FIX: Swap the merge order so user data overrides preset:

# CORRECT — user data overrides preset
data={**preset.get()[data["preset"]], **data}

Verify: POST /funcaptcha/createTask with {"preset": "github_signup", "blob": "real_blob_value"} should now use the real blob, not "undefined".

IP-Level Blocking by Arkose (2026-07-09)

CRITICAL: Arkose API returns {"error":"DENIED ACCESS"} (HTTP 200) for ALL presets when the IP is flagged. This is NOT a preset configuration issue — it's pure IP reputation. Tested with:

All presets (github, outlook, linkedin, twitter, snapchat, roblox)
blob=undefined, empty blob, no blob — all same result
curl_cffi with proper TLS impersonation — still blocked
The api.js endpoint loads fine (73KB), only the challenge endpoint rejects

Diagnosis: If ALL presets fail with "DENIED ACCESS", the IP is blocked. Rotate to a clean IP.

Verification: Test with a known-working preset (e.g. snapchat_register) — if that also returns "DENIED ACCESS", the IP is the problem, not the preset.

Workaround for GitHub: A persistent (warmed-up) Chrome profile bypasses the Arkose captcha entirely — the solver is not needed. See references/github-registration.md for the full pattern. This is the ONLY working approach for GitHub registration without a proxy.

Solver Crashes

Solver crashes are caught by Flask's generic except Exception: return invalid request — no error logging
Requires Node.js with jsdom (heavy dependency)
curl_cffi TLS impersonation may be detectable by some sites
WebGL fingerprint data in webgl.json (2.7MB) may need rotation

Installation Location

C:\Users\User\Desktop\funcaptcha-solver\ (cloned 2026-07-09)

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