Is the Bit Flipping attack on CBC mode possible if the IV is not know to the attacker?

Question

This is a follow up question to: Bit Flipping Attack on CBC Mode

which demonstrates that a bit flipping attack with a known IV is possible on CBC mode.

Is it safe to assume that the bit flicking attack is not possible if the attacker doesn't know the IV?

score 1 · Accepted Answer · answered Nov 02 '23 at 15:21

You would not be able to flip just a single bit as changing the previous ciphertext block will result in a randomized plaintext at that position.

However, as indicated in the other answer it is certainly possible to change block + a bit.

Furthermore, other attacks such as padding oracle attacks would probably still work.

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