A complete technical guide to Bypass Cloudflare's verification problem
Cloudflare's authentication system has become a major challenge for modern network access, especially for developers, data engineers, and ordinary users.
Ever been blocked by Cloudflare’s "Verify you’re human" page? You’re not alone. This happens when Cloudflare suspects automated traffic—whether you’re using a VPN, a sketchy network, or just have bad luck with cookies. Sometimes, clearing your browser cache, disabling extensions, or switching networks helps. For developers running into this while scraping or automating tasks, tweaking request headers or rotating IPs might do the trick.
This guide will explore the technical principles of Cloudflare's authentication mechanism in depth and provide comprehensive solutions from basic to advanced.
- Detect non-standard HTTP headers
- Verify browser API support
- Check JavaScript execution capabilities
- Analyze DOM operation timing characteristics
- Mouse movement trajectory analysis
- Page interaction timing mode
- Resource loading sequence detection
- Abnormal event triggering frequency
- IP reputation database (combined with Project Honeypet, etc.)
- ASN historical behavior analysis
- Geographic location risk assessment
- TLS fingerprinting
11. Initial request --> [CF edge node]
22. Lightweight detection --> [JS challenge/Cookie check]
3↓ (failed)
43. Deep verification --> [CAPTCHA/5-second shield]
5↓ (Still suspicious)
64. Block page --> [Error 1020/1015]
7
8Full configuration steps:
-
Visit whatsmyua to get the current UA
-
Make sure it matches your operating system version
1// Check WebGL fingerprint in the browser console
2const canvas = document.createElement('canvas');
3const gl = canvas.getContext('webgl');
4console.log(gl.getParameter(gl.VENDOR));
5
6-
Install common font packages (at least 20 standard fonts)
-
Disable rare fonts
-
Disable unconventional hardware features (such as special GPU extensions)
-
Maintain a reasonable screen resolution (avoid excessive use of 1920x1080)
1# Modify MTU value (need administrator privileges)
2netsh interface ipv4 set subinterface "Ethernet" mtu=1460 store=persistent
3
4# Disable TCP timestamp (may affect NAT)
5reg add HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters /v Tcp1323Opts /t REG_DWORD /d 0 /f
6
7- Use DoH (DNS over HTTPS):
1https://1.1.1.1/dns-query
2https://8.8.8.8/dns-query
3
4- Set up multiple DNS backups:
1# Linux example
2sudo resolvectl dns eth0 1.1.1.1 8.8.8.8 9.9.9.9
3
4Complete Python solution:
1import undetected_chromedriver as uc
2from selenium.webdriver.common.action_chains import ActionChains
3import random
4import time
5
6def setup_driver():
7options = uc.ChromeOptions()
8
9# Fingerprint configuration
10options.add_argument("--disable-blink-features=AutomationControlled")
11options.add_argument(f"--user-agent=Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/{random.randint(90,105)}.0.0.0 Safari/537.36")
12
13# Network simulation
14options.add_argument("--proxy-server=http://residential proxy IP:port")
15
16driver = uc.Chrome(options=options)
17
18# Override webdriver properties
19driver.execute_cdp_cmd("Page.addScriptToEvaluateOnNewDocument", {
20"source": """
21Object.defineProperty(navigator, 'webdriver', {
22get: () => undefined
23})
24"""
25})
26
27return driver
28
29def human_like_interaction(driver, url):
30driver.get(url)
31
32# Random mouse movement
33action = ActionChains(driver)
34for _ in range(random.randint(3,7)):
35x_offset = random.randint(-50, 50)
36y_offset = random.randint(-50, 50)
37action.move_by_offset(x_offset, y_offset).perform()
38time.sleep(random.uniform(0.2, 1.5))
39
40# Simulate scrolling
41scroll_pixels = random.randint(200, 800)
42driver.execute_script(f"window.scrollBy(0, {scroll_pixels})")
43
44# Random pause
45time.sleep(random.uniform(1, 3))
46
47return driver.page_source
48
491from curl_cffi import requests
2
3# Simulate Chrome's TLS fingerprint
4response = requests.get(
5"https://target.com",
6impersonate="chrome110",
7headers={
8"Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8",
9"Accept-Language": "en-US,en;q=0.5",
10}
11)
12
13- JA3 fingerprint
- HTTP/2 frame sequence
- Cipher suite sequence
- Extension list
1[Load balancer]
2↓
3[IP pool management] → Residential IP (60%) + Mobile IP (30%) + Computer room IP (10%)
4↓
5[Fingerprint management] → Chrome (70%) + Firefox (20%) + Safari (10%)
6↓
7[Behavior simulation engine] → Human mouse trajectory library + dwell time model
8↓
9[Exception handling] → Automatic verification code recognition + failure retry mechanism
10
11- 2Captcha: $0.5-1.0 per recognition
- Anti-Captcha: Support hCaptcha
- DeathByCaptcha: The most economical solution
1# Use OpenCV to preprocess CAPTCHA
2import cv2
3
4def preprocess_captcha(image_path):
5img = cv2.imread(image_path)
6gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
7_, thresh = cv2.threshold(gray, 150, 255, cv2.THRESH_BINARY_INV)
8kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (3,3))
9cleaned = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel)
10return cleaned
11
12Automated bypass technology:
- Extract the cf-chl-widget element in the page
- Get data-sitekey and data-action
- Solve it through 2Captcha's Turnstile dedicated API
- Inject verification result token
Request example:
1POST /cdn-cgi/challenge-platform/h/b/turnstile/verify HTTP/1.1
2Host: challenge.cloudflare.com
3Content-Type: application/json
4
5{
6"id": "widget-id",
7"response": "generated-token",
8"secret": "optional-secret-key"
9}
10
11Hybrid defense breakthrough strategy:
- Use real mobile device farms (Android+iOS)
- Combine computer vision to analyze protection changes in real time
- Dynamically adjust request intervals (0.5-5 seconds random)
- Deploy enhanced MITM proxy to analyze traffic
- Operate only on authorized targets
- Comply with robots.txt and API terms of use
- Request frequency does not exceed the normal human level
- Do not crawl personal privacy data (PII)
- Comply with GDPR/CCPA and other regulations
- Set a reasonable cache strategy
- Do not use it to steal competitor data
- Do not disrupt the normal operation of the target website
- Consider using the official API first
1class CFDefenseDetector:
2def __init__(self):
3self.cf_patterns = [
4r"cloudflare.*ray?id=",
5r"cdn-cgi/challenge-platform/",
6r"__cf_chl_managed="
7]
8
9def is_cf_blocked(self, html):
10return any(re.search(p, html, re.I) for p in self.cf_patterns)
11
12| Indicator | Threshold | Countermeasures |
|---|---|---|
| Verification code occurrence rate | > 15% | Switch IP pool |
| Request delay | > 5s | Adjust rate limit |
| Success rate | < 85% | Update fingerprint library |
| JS challenge frequency | > 30% | Strengthen browser simulation |
- Generate Human Mouse Trajectory Using GAN
- Optimize Request Strategies with Reinforcement Learning
- Post-Quantum Cryptography Applications
- NIST Standardized Algorithm Integration
- WebGPU Fingerprinting
- Audio Context Analysis
The solutions provided in this guide need to be used in combination according to specific scenarios, and it is recommended to update the adversarial strategy regularly (at least once a quarter). As Cloudflare continues to upgrade its defense system, keeping the technology updated is the key to long-term success.
