One more step
This is the current page that CloudFlare serves up when they decide to block a user from accessing a web site:
Tor users have been seeing a lot of it recently because of how CloudFlare’s reputation system handles multiple people sharing a single IP address. If a spambot decides to use an IP address that is also being shared by humans then everyone gets punished for the bot’s behavior.
Vanity block pages
I tried a couple of different styles for the error page, but mimicking the browser’s own error page felt the best. It’s got that authoritative tone that says the internet is broken in a serious and fundamental way and that seemed to fit the feeling.
First and foremost are links to archived copies of the page, but there’s also the option to solve captchas. That works by scraping the CloudFlare block page and Google’s captcha service then presenting it in a clean, easy-to-use format. Scraping means it’s super brittle to any changes to the block or captcha pages but it has the advantage that you don’t have to allow arbitrary scripts to run.
Anonymity loves company
I’m not going to offer the extension as a downloadable package though, only as source. It’s got flaws that defeat its purpose as a privacy-enhancing tool.
Namely, it alters how browsers load the block page in a way that’s detectable by CloudFlare, Google or in fact any other site that might decide to test whether the extension is installed. Currently this extension has no users so anybody that decided to install it would stand out from the crowd.
Also it doesn’t even run in Firefox or Tor Browser. I developed it using the WebExtensions API and Firefox’s implementation is currently missing some parts needed for it to work properly.
Making this vanity block page was fun, but it doesn’t touch the bigger issue that many site owners have granted CloudFlare the power to block arbitrary users from reading their sites. If anything, this winter’s flare-up of block pages has served as a reminder of how large the proportion of web traffic flowing through CloudFlare has become.