Bug#654764: Mitigate B.E.A.S.T attack

[Stefan Fritsch <sf@sfritsch.de>]

On Thursday 05 January 2012, Mathieu Parent wrote:
> The BEAST vulnerability [1] "can be prevented by removing all CBC
> ciphers from your list of allowed ciphers—leaving only the RC4
> cipher".

I don't think we want to do that. The normal RC4 algorithms (i.e. not 
ECDHE-*-RC4*) don't provide perfect forward secrecy. So you would 
improve the security in one regard (mitigate BEAST vulnerability even 
if the client does not implement a work-around) but worsen it in 
another regard.

AFAIK, NSS, which is used by Chrome and Firefox, has had a BEAST 
workaround for some time now. So, the suggested change would worsen 
the security for a significant part of the user base.