Have you ever had your web scrapers blocked when attempting to extract data from certain sites? Chances are good a WAF was behind that.
WAF stands for Web Application Firewall. It's a system designed specifically to prevent scrapers and bots from accessing web content.
But with the right techniques, you can break through WAF defenses to scrape anything. This guide will teach you how.
What is a WAF and Why You Need to Bypass it
A WAF operates on top of a web server to analyze all incoming traffic. It applies rule sets and machine learning models to detect threats and block suspicious access attempts.
For web scrapers, even relatively simple bots making a lot of benign requests can trigger WAF protections. Common results include getting:
- IP banned
- Hit with CAPTCHAs
- Flagged via device fingerprinting
Without a way around these measures, your scrapers won't be able to do their jobs. So understanding how to bypass WAFs is essential.
Identifying the WAF
The first step is figuring out which WAF (if any) a target site uses. The major players are Cloudflare, Akamai, PerimeterX and DataDome.
To detect the WAF, you can:
- Check for indicators in the page HTML
- Analyze HTTP response headers
- Attempt automated requests and review error responses
Confirming the specific WAF lets you research bypass strategies tailored to its protection methods.
Techniques to Bypass WAF Defenses
Here are proven techniques to avoid getting blocked while scraping sites protected by WAFs:
1. Route Traffic Through Residential Proxies
WAFs often block scrapers based on their IP addresses. Using residential proxies assigns you new IP addresses associated with real home or business internet connections.
This makes your traffic appear more human-like and harder to detect.
Bright Data offers reliable residential proxies starting at just $500 per month for 40GB of traffic.
2. Configure Fortified Headless Browsers
Browser automation tools like Selenium and Puppeteer are useful for scraping dynamic sites. But they can also make your bots easy for WAFs to catch.
3. Solve CAPTCHAs Automatically
Completely avoiding CAPTCHAs usually requires configuration tweaks combined with good proxies. But when you do hit a CAPTCHA, services like Anti-Captcha can solve them automatically.
The APIs submit your CAPTCHAs, receive back text or image solutions, and feed those back to your bot to continue scraping.
4. Prevent Falling Into Hidden Honeypots
Honeypots are hidden traps that bots can fall into but humans don't see. Train your scrapers to avoid anything not visible in the browser, like links with
display: none styling.
Proxy services like Bright Data also handle honeypots automatically in most cases.
5. Overcome Browser Fingerprinting
Browser fingerprinting gathers information on your browser, OS, device, etc. to assign you a unique ID. Route your traffic through proxies using a diverse pool of devices to make fingerprinting much harder.
6. Fool Behavior and Event Tracking
Many WAFs monitor how you interact with pages to profile your behavior. Mimic human patterns as much as possible, with natural mouse movements, scrolling, and reading times.
Bypassing WAF protections certainly isn't trivial. There's no one simple trick. The best approach involves:
- Understanding the specifics of the WAF
- Leveraging residential proxies
- Configuring difficult-to-detect browsers
- Accounting for various bot detection methods
The scripts and configuration required take significant development time. Rather than building everything from scratch, services like Bright Data handle proxy management, browser customization, and WAF circumvention for you.
WAF evasion will always be something of an arms race with new techniques emerging constantly. But with the right knowledge and tools, any site can be scraped!