I believe the exact opposite.
One (of many) reasons is that it can make your code less secure, by hiding your security mistakes from you.
If your WAF obscures escaping issues during your own testing and usage you could very easily let those escaping issues go unresolved - leaving you vulnerable to any creative attacker who can outsmart your WAF.
https://knowyourmeme.com/memes/events/star-wars-battlefront-...
The problem is that generally you're breaking actual valid use cases as the tradeoff to being another layer of defense against hypothetical vulnerabilities.
Yes, discussing the hosts file is a valid use case.
Yes putting angle brackets in the title of your message is valid use case your users are going to want.
Yes putting "mismatched" single quotes inside double quotes is a thing users will do.
Yes your users are going to use backslashes and omit spaces in a way that looks like attempts at escaping characters.
(All real problems I've seen caused by overzealous security products)
It is net zero for security and net negative for user experience, so having it is worse than not having it.
The part that’s not said outloud is that a lot of “computer security” people aren’t concerned with understanding the system. If they were, they’d be engineers. They’re trying to secure it without understanding it.
The way I assume it works in practice on a real team is that after some time, most of your team will have no idea how the WAF works and what it protects against, where and how it is configured… but they know it exists, so they will no longer pay attention to security because “we have a tool for that”, especially when they should have finished that feature a week ago…
