Bypass Word Filter Bug

I recently saw a post made by some sketchy account that had a cuss word in it. I had heard before that WeAreDevs has a word blacklist, and I knew that they had done something to bypass it. So, analyzed a cuss word they had in their post, and found a simple bypass that literally anyone can do with no skill whatsoever. I found that the 4 letter cuss word somehow was actually 8 letters/characters. This means that they had to have put invisible extra characters into the word, tricking the blacklist into thinking it wasn't a blacklisted word. Upon putting it into a character detector, I found it contained a "Zero-Widthspace" which is an invisible character that still technically counts as a character.

I did more research into this Zero-Widthspace and found this website containing an entire list of characters that were invisible yet still a character.

So, imagine the word

• Apple
• Apple

Can you tell a difference? No? Exactly. They look the same, yet 1 is filled with invisible characters while the other isn't. Because Apple combined with these characters isn't in the blacklist, well, it will let it through as a non blacklisted word.

The fix to this? I propose just simply blocking any characters like the Zero-Widthspace. Easiest fix ever for an easy problem.

To conclude this,

PLEASE DONT TEST THIS. You can get in trouble for it, and I'm adding a disclaimer so when people are getting in trouble for cussing it's not my fault.