Got a warning for my blog going over 100GB in bandwidth this month… which sounded incredibly unusual. My blog is text and a couple images and I haven’t posted anything to it in ages… like how would that even be possible?
Turns out it’s possible when you have crawlers going apeshit on your server. Am I even reading this right? 12,181 with 181 zeros at the end for ‘Unknown robot’? This is actually bonkers.
Edit: As Thunraz points out below, there’s a footnote that reads “Numbers after + are successful hits on ‘robots.txt’ files” and not scientific notation.
The author demonstrated that the challenge can be solved in 17ms however, and that is only necessary once every 7 days per site. They need less than a second of compute time, per site, to be able to send unlimited requests 365 days a year.
The deterrent might work temporarily until the challenge pattern is recognised, but there’s no actual protection here, just obscurity. The downside is real however for the user on an old phone that must wait 30 seconds, or like the blogger, a user of a text browser not running JavaScript. The very need to support an old phone is what defeats this approach based on compute power, as it’s always a trivial amount for the data center.
Please tell me how you’re gonna un-obscure a proof-of-work challenge requiring calculation of hashes.
And since the challenge is adjustable, you can make it take as long as you want.
You just solve it as per the blog post, because it’s trivial to solve, as your browser is literally doing so in a slow language on a potentially slow CPU. It’s only solving 5 digits of the hash by default.
If a phone running JavaScript in the browser has to be able to solve it you can’t just crank up the complexity. Real humans will only wait tens of seconds, if that, before giving up.