3 ms·
> chances are it will cause the decrypted plaintext to be gibberish with many invalid/unprintable ascii characters. Not necessarily. If the plaintext you're t
by d-z-m 3y ago
> chances are it will cause the decrypted plaintext to be gibberish with many invalid/unprintable ascii characters.
Not necessarily. If the plaintext you're trying to modify is in the first ciphertext block(which in this scenario is likely the case), you can modify a byte in the IV(assuming the IV is stored alongside the ciphertext) to modify the corresponding byte in the first plaintext block without a trace.
> Is this a serious issue for this use case?
In my opinion this whole use case is an issue. Why give an attacker access to your encrypted passwords?
- gruez 3y ago>you can modify a byte in the IV(assuming the IV is stored alongside the ciphertext) to modify the corresponding byte in the first plaintext block without a trace. So with this vulnerability, the attacker can... cause you to enter a wrong password. That's kinda annoying, but at the end of the day it's a DoS attack, and even though using AEAD ciphers would prevent this specific attack, it won't prevent other DoS attacks (eg. blocking/mangling all DNS traffic).
- d-z-m 3y agoIndeed, we're kind of lost in the weeds here. The real question is...why do this in the first place? It isn't a good idea.