Re:Multitun – Tunnel arbitrary traffic through an innocuous ...
by rapidally2 on Friday November 21, 2014 @01:14AM
(#8640068)
The IV doesn't start as zero; it starts as a random number.
Re:Multitun – Tunnel arbitrary traffic through an innocuous ...
by ryan-c on Friday November 21, 2014 @02:32AM
(#8640218)
Oh, you are correct. It's chosen by the client here:
https://github.com/covertcodes/multitun/blob/master/multitun...
Based on a quick skim:
* no kdf on the password, just SHA-2-224(password)
* uses the same key and iv (which always starts as 0) in both directions
* uses CFB mode without a MAC, which has malleability issues (IIRC you can flip bits in a ciphertext block, and the same bits will be flipped in the plaintext, but the rest of the stream will be garbage).
* the authentication used is pretty sketchy (the key is fixed at 16 bytes and PW_LEN 15, so ljust shouldn't be doing anything):
Reminds me of this: https://www.cs.auckland.ac.nz/~pgut001/pubs/linux_vpn.txt