When accessing any CloudFlare protected page Cloudflare’s Turnstile process begins. This system, which serves as an alternative to traditional CAPTCHAs, helps determine whether the user is human or a bot. Upon opening the page in an Incognito Mode, the user encounters a waiting room after successfully solving the Turnstile challenge.
Behind the scenes, multiple POST requests are sent to Cloudflare’s servers, transmitting encrypted data:
While the exact contents of this data remain unknown, it likely includes details about user’s browser settings (browser fingerprinting) and hardware configuration. Cloudflare’s algorithms analyze these parameters to identify any suspicious activity, such as the presence of a webdriver hint that could suggest automated browsing.
Once user’s browser and hardware are confirmed as legitimate, Cloudflare issues a cf_clearence cookie:
This cookie, as seen at the figure above, grants access to the website for a year in my case, allowing an scrape engineer to utilize it in their scrapers during that time without needing to repeat verification steps. This efficient process helps protect websites while ensuring genuine users can access content smoothly.
Recap
As we know the way Cloudflare works at a high level, we can do some reverse-engineering for it. Getting the Cloudflare clearance cookie is a way to bypass a website guarded by it.