Re: [TLS] Another IRINA bug in TLS
Nikos Mavrogiannopoulos <nmav@redhat.com> Thu, 21 May 2015 11:51 UTC
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From: Nikos Mavrogiannopoulos <nmav@redhat.com>
To: Florian Weimer <fweimer@redhat.com>
Date: Thu, 21 May 2015 13:51:44 +0200
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Subject: Re: [TLS] Another IRINA bug in TLS
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On Thu, 2015-05-21 at 13:42 +0200, Florian Weimer wrote: > On 05/21/2015 01:31 PM, Santiago Zanella-Beguelin wrote: > > > Deprecating non-safe DH primes and having clients test primality of p and (p-1)/2 goes a long way. It doesn't rule out all weak groups or trapdoors. > > I need something which prevents MITM attacks and can be applied as a > software update without configuration changes, and without extensive > testing because it is relatively risk-free. Well, you assume that the so-called "safe primes" are universally used, which is not really the case. Expecting all servers sending these parameters wouldn't really work. In addition the check you have isn't complete, you'll also need to calculate the order of the generator and verify it is sufficient. I don't think that approach is close to being reasonable to be done on every connection. > Rejecting handshakes in clients without additional measures risks that > (a) additional handshakes fail, leading to service outages and (b) > clients will fall back no encryption at all (after manual intervention, > or automatically in case of SMTP with STARTTLS and opportunistic > encryption). The way I tackled the issue in gnutls is to prioritize the ciphersuites of the client in that order: ECDHE, RSA, DHE, and perform a size check on the DHE ones. regards, Nikos
- [TLS] Another IRINA bug in TLS Watson Ladd
- Re: [TLS] Another IRINA bug in TLS Tom Ritter
- Re: [TLS] Another IRINA bug in TLS Ilari Liusvaara
- Re: [TLS] Another IRINA bug in TLS Nikos Mavrogiannopoulos
- Re: [TLS] Another IRINA bug in TLS Aaron Zauner
- Re: [TLS] Another IRINA bug in TLS Nikos Mavrogiannopoulos
- Re: [TLS] Another IRINA bug in TLS Watson Ladd
- Re: [TLS] Another IRINA bug in TLS Salz, Rich
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Martin Rex
- Re: [TLS] Another IRINA bug in TLS Peter Gutmann
- Re: [TLS] Another IRINA bug in TLS Nikos Mavrogiannopoulos
- Re: [TLS] Another IRINA bug in TLS Nikos Mavrogiannopoulos
- Re: [TLS] Another IRINA bug in TLS Yuhong Bao
- Re: [TLS] Another IRINA bug in TLS Karthikeyan Bhargavan
- Re: [TLS] Another IRINA bug in TLS Florian Weimer
- Re: [TLS] Another IRINA bug in TLS Nikos Mavrogiannopoulos
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Peter Gutmann
- Re: [TLS] Another IRINA bug in TLS Yngve N. Pettersen
- Re: [TLS] Another IRINA bug in TLS Peter Gutmann
- Re: [TLS] Another IRINA bug in TLS Yoav Nir
- Re: [TLS] Another IRINA bug in TLS Antoine Delignat-Lavaud
- Re: [TLS] Another IRINA bug in TLS Florian Weimer
- Re: [TLS] Another IRINA bug in TLS Nikos Mavrogiannopoulos
- Re: [TLS] Another IRINA bug in TLS Florian Weimer
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Florian Weimer
- Re: [TLS] Another IRINA bug in TLS Nikos Mavrogiannopoulos
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Aaron Zauner
- Re: [TLS] Another IRINA bug in TLS Aaron Zauner
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Nikos Mavrogiannopoulos
- Re: [TLS] Another IRINA bug in TLS Dave Garrett
- Re: [TLS] Another IRINA bug in TLS Aaron Zauner
- Re: [TLS] Another IRINA bug in TLS Watson Ladd
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Dan Brown
- Re: [TLS] Another IRINA bug in TLS Watson Ladd
- Re: [TLS] Another IRINA bug in TLS Dan Brown
- Re: [TLS] Another IRINA bug in TLS Jeffrey Walton
- Re: [TLS] Another IRINA bug in TLS Nico Williams
- Re: [TLS] Another IRINA bug in TLS Peter Gutmann
- Re: [TLS] Another IRINA bug in TLS Jeffrey Walton
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Kurt Roeckx
- Re: [TLS] Another IRINA bug in TLS Karthikeyan Bhargavan
- Re: [TLS] Another INRIA bug in TLS Daniel Kahn Gillmor
- Re: [TLS] Another INRIA bug in TLS Andrei Popov
- Re: [TLS] Another INRIA bug in TLS Martin Thomson
- Re: [TLS] Another INRIA bug in TLS Martin Thomson
- Re: [TLS] Another IRINA bug in TLS Tony Arcieri
- Re: [TLS] Another INRIA bug in TLS Jeffrey Walton
- Re: [TLS] Another INRIA bug in TLS Tanja Lange
- Re: [TLS] Another IRINA bug in TLS Tanja Lange
- Re: [TLS] Another INRIA bug in TLS Andrey Jivsov
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another INRIA bug in TLS Martin Thomson
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another INRIA bug in TLS Karthikeyan Bhargavan
- Re: [TLS] Another IRINA bug in TLS Kurt Roeckx
- Re: [TLS] Another IRINA bug in TLS Kurt Roeckx
- Re: [TLS] Another INRIA bug in TLS Stephen Farrell
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another INRIA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Watson Ladd
- Re: [TLS] Another IRINA bug in TLS Jeffrey Walton
- Re: [TLS] Another IRINA bug in TLS Watson Ladd
- Re: [TLS] Another IRINA bug in TLS Peter Gutmann
- Re: [TLS] Another IRINA bug in TLS Karthikeyan Bhargavan
- Re: [TLS] Another IRINA bug in TLS Peter Gutmann
- Re: [TLS] Another IRINA bug in TLS Tanja Lange
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Peter Gutmann
- Re: [TLS] Another IRINA bug in TLS Santiago Zanella-Beguelin
- Re: [TLS] Another IRINA bug in TLS Andrey Jivsov
- Re: [TLS] Another IRINA bug in TLS Hubert Kario
- Re: [TLS] Another IRINA bug in TLS Hubert Kario
- Re: [TLS] Another IRINA bug in TLS Karthikeyan Bhargavan
- Re: [TLS] Another IRINA bug in TLS Karthikeyan Bhargavan
- Re: [TLS] Another IRINA bug in TLS Hubert Kario
- Re: [TLS] Another IRINA bug in TLS Daniel Kahn Gillmor
- Re: [TLS] Another IRINA bug in TLS Jeffrey Walton
- Re: [TLS] Another IRINA bug in TLS Andrei Popov
- Re: [TLS] Another IRINA bug in TLS Nico Williams
- Re: [TLS] Another INRIA bug in TLS Nico Williams