Here is the text of the NIST sp800-63b Digital Identity Guidelines.
I’ve seen sites truncate when setting, but not on checking. So you set a password on a site with no stated limit, go to use said password, and get locked out. It’s infuriating
Years back, I had that happen on PayPal of all websites. Their account creation and reset pages silently and automatically truncated my password to 16 chars or something before hashing, but the actual login page didn’t, so the password didn’t work at all unless I backspaced it to the character limit. I forgot how I even found that out but it was a very frustrating few hours.
Banks usually have the absolute worst password policies. It’s typically because their backend is some crusty mainframe from the 80s that limits inputs to something absurdly insecure by today’s standards and they’ve kicked the upgrade can down the road for so long now that it’s a staggeringly monumental task to rewrite it all. Thankfully most of them have upgraded at this point, but every now and then you still find one that’s got ridiculous limits like a maximum password length of 8 and only alphanumeric characters (with no 2FA obviously).
Another ridiculous policy I’ve seen (many years ago) is logging in too fast. I used to get locked out of my banks website all the time and I used autotype with KeePass so I was baffled when it wouldn’t get accepted. Eventually I had a thought to slow down the typing mechanism and suddenly I didn’t get locked out anymore.
