Re: [TLS] TLS 1.3 - Support for compression to be removed

Julien ÉLIE <julien@trigofacile.com> Sun, 20 September 2015 14:54 UTC

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Subject: Re: [TLS] TLS 1.3 - Support for compression to be removed
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Hi Karthik,

> It may well be true that some (typically unauthenticated) application
> protocols on top of TLS can survive TLS compression, but it is
> unlikely.
[...]
> HTTP is a particularly bad case because the attacker can potentially
> inject arbitrary data before (and after) the secret. With NNTP you
> may escape the worst of this adversary, but you probably won’t find
> any TLS expert willing to say that compressing the password is ok.

OK, many thanks for the illustration!

So in fact, to be safer, authentication commands should either be sent 
uncompressed or be more complex than they currently are (for instance 
with the insertion of random data with random length along with the 
authentication command).

If TLS 1.3 is used, so without compression facility, adding a new 
COMPRESS command to NNTP will not help if how authentication is done is 
not strenghtened at the same time, won't it?
Or AUTHINFO is not a valid command after the use of COMPRESS.

-- 
Julien ÉLIE

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