# Browser Fingerprint Checks

What anti-bot systems check and how to evade.

## Detection Layers

```
┌─────────────────────────────────────────────┐
│           Layer 1: Network/IP               │
│  • IP reputation score                      │
│  • Datacenter vs residential                │
│  • Geo-location consistency                 │
├─────────────────────────────────────────────┤
│           Layer 2: TLS Fingerprint          │
│  • JA3/JA4 hash                            │
│  • Cipher suite order                       │
│  • TLS extensions                           │
├─────────────────────────────────────────────┤
│           Layer 3: HTTP Headers             │
│  • User-Agent consistency                   │
│  • Header order                             │
│  • Accept-Language                          │
├─────────────────────────────────────────────┤
│           Layer 4: Browser Fingerprint      │
│  • navigator.webdriver                      │
│  • Canvas/WebGL hash                        │
│  • Audio fingerprint                        │
│  • Font enumeration                         │
├─────────────────────────────────────────────┤
│           Layer 5: Behavioral               │
│  • Mouse movements                          │
│  • Scroll patterns                          │
│  • Timing analysis                          │
│  • Click patterns                           │
└─────────────────────────────────────────────┘
```

## Specific Checks & Countermeasures

### 1. navigator.webdriver

**What:** `navigator.webdriver` returns `true` for automated browsers.

**Check:**
```javascript
navigator.webdriver  // true = bot
```

**Countermeasure:**
- Nodriver: Automatically patches
- Camoufox: Patched at C++ level
- Playwright-stealth: `delete navigator.webdriver` (weak, can be detected)

### 2. Chrome DevTools Protocol (CDP)

**What:** Presence of CDP side-channels reveals automation.

**Check:**
```javascript
// Sites check for CDP artifacts
window.cdc_adoQpoasnfa76pfcZLmcfl_Array
window.cdc_adoQpoasnfa76pfcZLmcfl_Promise
```

**Countermeasure:**
- Nodriver: Uses CDP but patches artifacts
- Camoufox: No CDP (native Firefox)
- Patchright: Patches CDP artifacts

### 3. Canvas Fingerprint

**What:** Each GPU/driver combo renders slightly differently.

**Check:**
```javascript
canvas.toDataURL()  // Unique hash per system
```

**Countermeasure:**
- Camoufox: Injects deterministic noise
- Some detection tools look for perfectly identical canvas = bot

### 4. WebGL Fingerprint

**What:** GPU vendor/renderer strings.

**Check:**
```javascript
gl.getParameter(gl.RENDERER)  // "ANGLE (Intel HD Graphics)"
gl.getParameter(gl.VENDOR)    // "Google Inc."
```

**Countermeasure:**
- Camoufox: Spoofs to common values
- Avoid VMs with "llvmpipe" or "SwiftShader" (instant bot flag)

### 5. Audio Fingerprint

**What:** AudioContext processing variations.

**Check:**
```javascript
new AudioContext().createOscillator()  // Unique waveform
```

**Countermeasure:**
- Camoufox: Adds noise to audio processing

### 6. Font Enumeration

**What:** Bots often have minimal fonts installed.

**Check:**
```javascript
// Test if specific fonts render
document.fonts.check('12px "Segoe UI"')
```

**Countermeasure:**
- Install standard fonts in your environment
- Camoufox: Spoofs font list

### 7. Screen/Window Size

**What:** Unusual dimensions = bot.

**Check:**
```javascript
screen.width, screen.height
window.innerWidth, window.innerHeight
```

**Countermeasure:**
- Use standard resolutions: 1920x1080, 1366x768
- Avoid: 800x600, odd dimensions

### 8. Timezone Consistency

**What:** Timezone must match IP geo-location.

**Check:**
```javascript
Intl.DateTimeFormat().resolvedOptions().timeZone
new Date().getTimezoneOffset()
```

**Countermeasure:**
- Set timezone to match proxy location:
  ```bash
  TZ="America/New_York" python script.py
  ```

### 9. Language Consistency

**What:** Browser language should match geo.

**Check:**
```javascript
navigator.language       // "en-US"
navigator.languages      // ["en-US", "en"]
```

**Countermeasure:**
- Configure browser locale to match proxy:
  ```python
  # Camoufox
  async with AsyncCamoufox(locale="en-US") as browser:
  ```

### 10. Hardware Concurrency

**What:** VMs often report 1-2 CPUs.

**Check:**
```javascript
navigator.hardwareConcurrency  // 1 or 2 = suspicious
```

**Countermeasure:**
- Camoufox: Spoofs to 4-8
- Or use real hardware, not minimal VM

### 11. Headless Detection

**What:** Multiple signals reveal headless mode.

**Checks:**
```javascript
navigator.plugins.length === 0
navigator.mimeTypes.length === 0
window.chrome === undefined
```

**Countermeasure:**
- Use "new headless" mode: `headless="new"`
- Or run headed in Xvfb
- Camoufox headless is well-patched

### 12. Mouse/Keyboard Events

**What:** Bots often have no mouse history.

**Check:**
```javascript
// Sites track mouse movement patterns
document.addEventListener('mousemove', analyze)
```

**Countermeasure:**
- Inject random mouse movements
- Nodriver/Camoufox: Built-in human-like movement
- Don't teleport cursor - use bezier curves

## Test Sites

Check your stealth setup:

| Site | What It Tests |
|------|--------------|
| https://bot.sannysoft.com | Comprehensive bot detection |
| https://browserleaks.com | All fingerprints |
| https://nowsecure.nl | Cloudflare detection |
| https://pixelscan.net | Bot detection score |
| https://abrahamjuliot.github.io/creepjs | Advanced fingerprinting |

## Tool Comparison

| Check | Camoufox | Plain Playwright |
|-------|----------|------------------|
| webdriver | ✅ | ❌ |
| CDP artifacts | ✅ (no CDP) | ❌ |
| Canvas | ✅ | ❌ |
| WebGL | ✅ | ❌ |
| Audio | ✅ | ❌ |
| Fonts | ✅ | ❌ |
| Headless | ✅ | ❌ |
| TLS | ✅ | ❌ |

Legend: ✅ = patched, ❌ = detected