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Re: [TLS] Expanded alert codes. [Was Re: Genart last call review of draft-ietf-tls-tls13-24]

Ion Larranaga Azcue <ilarra@s21sec.com> Sun, 01 April 2018 10:00 UTC

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From: Ion Larranaga Azcue <ilarra@s21sec.com>
To: Peter Gutmann <pgut001@cs.auckland.ac.nz>, Eric Rescorla <ekr@rtfm.com>
CC: General Area Review Team <gen-art@ietf.org>, "Dale R. Worley" <worley@ariadne.com>, IETF discussion list <ietf@ietf.org>, "draft-ietf-tls-tls13.all@ietf.org" <draft-ietf-tls-tls13.all@ietf.org>, "<tls@ietf.org>" <tls@ietf.org>
Thread-Topic: [TLS] Expanded alert codes. [Was Re: Genart last call review of draft-ietf-tls-tls13-24]
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Date: Sun, 01 Apr 2018 10:00:53 +0000
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Subject: Re: [TLS] Expanded alert codes. [Was Re: Genart last call review of draft-ietf-tls-tls13-24]
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Anyway, I don't mean I'm against the idea of the extended errors extensions... Only that let's not take it lightly. It can be a good debugging tool but also a risky one.

________________________________________
De: TLS <tls-bounces@ietf.org> en nombre de Ion Larranaga Azcue <ilarra@s21sec.com>
Enviado: domingo, 1 de abril de 2018 11:55
Para: Peter Gutmann; Eric Rescorla
Cc: General Area Review Team; Dale R. Worley; IETF discussion list; draft-ietf-tls-tls13.all@ietf.org; <tls@ietf.org>
Asunto: Re: [TLS] Expanded alert codes. [Was Re: Genart last call review of draft-ietf-tls-tls13-24]

Of course not. I mean an attacker who is specially interested in this server and knows that someone has requested a debug window on it.

________________________________________
De: Peter Gutmann <pgut001@cs.auckland.ac.nz>
Enviado: domingo, 1 de abril de 2018 10:14
Para: Ion Larranaga Azcue; Eric Rescorla
Cc: IETF discussion list; General Area Review Team; draft-ietf-tls-tls13.all@ietf.org; Dale R. Worley; <tls@ietf.org>
Asunto: Re: [TLS] Expanded alert codes. [Was Re: Genart last call review of draft-ietf-tls-tls13-24]

Ion Larranaga Azcue <ilarra@s21sec.com> writes:

>And for the malicious user that, knowing the server is currently in debug
>mode and returning extended errors, can more easily perform attacks on it...

If there's someone on the Internet who can scan every TLS server on the planet
once a minute to see a brief debug window open up, and then perform something
like a million-message-attack using a single debug message, then they're kinda
wasting their abilities in attacking TLS servers...

Peter.


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