There is an information integrity vulnerability in the SSH1 protocol that allows RC4 encrypted packets to be modified without notice.
Client has requested RC4 and server supports it.
Because the CRC has been modified to account for the "addition" of M, the CRC integrity check on the victim's SSH client will pass.
Attackers can modify or logically delete arbitrary SSH packets.
SSH Secure Communications recommends disabling RC4 in SSH1 or upgrading to SSH2.
SSH Communications Security
The CERT/CC thanks Antti Huima, Tuomas Aura, and Janne Salmi for their analysis and Tatu Ylonen for bringing this vulnerability to our attention.
This document was written by Jeffrey P. Lanza.
|Date First Published:||2001-01-18|
|Date Last Updated:||2002-03-05 20:22 UTC|