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

Julien ÉLIE <julien@trigofacile.com> Sun, 20 September 2015 09:02 UTC

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From: Julien ÉLIE <julien@trigofacile.com>
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Subject: Re: [TLS] TLS 1.3 - Support for compression to be removed
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Hi Rich,

> It is widely recognized that in many cases, TLS-level compression is
> flawed (for example NNTP authinfo?).

Though I've read a few pages explaining how CRIME and BEAST attacks 
work, I still do not see well how TLS-level compression would make NNTP 
vulnerable.
Same thing for POP or IMAP I believe.

The news server does not leak information.  The responses are just OK or KO.
For instance:

AUTHINFO USER test
381 Enter password
AUTHINFO PASS test
281 Authentication succeeded

or in the case of an authentication failure:

AUTHINFO USER test
381 Enter password
AUTHINFO PASS badpassword
481 Authentication failed



How compression would make NNTP weaker?
(Brute-force attack is still necessary, even with compression enabled.)

-- 
Julien ÉLIE

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