30 Mar
2012
30 Mar
'12
6:03 a.m.
On 30/03/12 10:38, Fajar A. Nugraha wrote:
How easy is it to crack such a password? An authentification wouldn't have happened but the attacker would have had the encrypted usernames and passwords.
They won't.
Not immediately. But MSCHAP is a complex (and old) algorithm, and it is possible to perform a known-ciphertext attack. See e.g. http://code.google.com/p/mschapv2acc/ I'd wager this attack could be improved a lot by capturing multiple chal/resp pairs and doing clever stuff with them, but my crypto maths are very rusty by this point. The takeaway is that you should not be doing MSCHAP over an insecure channel, IMO.