Re: [TLS] 0-RTT and Anti-Replay
Eric Rescorla <ekr@rtfm.com> Sun, 22 March 2015 22:30 UTC
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From: Eric Rescorla <ekr@rtfm.com>
Date: Sun, 22 Mar 2015 15:30:10 -0700
Message-ID: <CABcZeBOAuraUEHbi1c1qJuBhZMgkSfx1ukB4ihtabNRE73KVRQ@mail.gmail.com>
To: Mohamad Badra <mbadra@gmail.com>
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Cc: "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] 0-RTT and Anti-Replay
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On Sun, Mar 22, 2015 at 3:26 PM, Mohamad Badra <mbadra@gmail.com> wrote: > Hi Eric, > > >> Client Attacker Server >> >> ClientHello [+0-RTT] ------------> >> "POST /buy-something" -----------> >> >> ClientHello [+0-RTT] ---------------> >> "POST /buy-something" --------------> >> >> [Processes purchase] >> <---------- ServerHello [accept 0-RTT] >> (+ rest of handshake) >> >> >> The attacker just discards the server's response and then the server >> somehow forces the server to reboot (this is the hard part). >> >> Once the server has rebooted, the attacker re-sends the client's >> initial flight then just forwards data back and forth to the client. >> >> Client Attacker Server >> ClientHello [+0-RTT] ---------------> >> "POST /buy-something" --------------> >> >> <-------------------------------------- ServerHello [reject 0-RTT] >> (+ rest of handshake) >> >> Finished ---------------------------------------------------------> >> "Post /buy-something" --------------------------------------------> >> [Processes purchase] >> >> At this point, you've mounted a successful replay attack. Obviously >> this is not that great an attack because it requires you to be able to >> force a reboot and also get in under the client's timeout window. >> > > > According to draft-rescorla-tls13-new-flows-01: > > The EncryptedExtensions MUST include an ART indicator that matches > the client's ART so that the client knows that the 0-RTT handshake > was successful and that the client's application_data was accepted. > > > > I wonder why the Server doesn't include an indicator in his reject > (encrypted indicator) so the client will avoid sending its request again. > This would basically be option #3, namely that this data is unreliable. Best, -Ekr (BTW, based on what a server can reject after a reboot) > > Best regards > Mohamad >
- [TLS] 0-RTT and Anti-Replay Eric Rescorla
- Re: [TLS] 0-RTT and Anti-Replay Mohamad Badra
- Re: [TLS] 0-RTT and Anti-Replay Eric Rescorla
- Re: [TLS] 0-RTT and Anti-Replay Stephen Checkoway
- Re: [TLS] 0-RTT and Anti-Replay Daniel Kahn Gillmor
- Re: [TLS] 0-RTT and Anti-Replay Andrey Jivsov
- Re: [TLS] 0-RTT and Anti-Replay Eric Rescorla
- Re: [TLS] 0-RTT and Anti-Replay Martin Thomson
- Re: [TLS] 0-RTT and Anti-Replay Andrey Jivsov
- Re: [TLS] 0-RTT and Anti-Replay Colm MacCárthaigh
- Re: [TLS] 0-RTT and Anti-Replay Colm MacCárthaigh
- Re: [TLS] 0-RTT and Anti-Replay Nico Williams
- Re: [TLS] 0-RTT and Anti-Replay Ilari Liusvaara
- Re: [TLS] 0-RTT and Anti-Replay Nico Williams
- Re: [TLS] 0-RTT and Anti-Replay Nico Williams
- Re: [TLS] 0-RTT and Anti-Replay Martin Thomson
- Re: [TLS] 0-RTT and Anti-Replay Eric Rescorla
- Re: [TLS] 0-RTT and Anti-Replay Roland Zink
- Re: [TLS] 0-RTT and Anti-Replay Martin Thomson
- Re: [TLS] 0-RTT and Anti-Replay Colm MacCárthaigh
- Re: [TLS] 0-RTT and Anti-Replay Viktor Dukhovni
- Re: [TLS] 0-RTT and Anti-Replay Martin Thomson
- Re: [TLS] 0-RTT and Anti-Replay Brian Sniffen
- Re: [TLS] 0-RTT and Anti-Replay Salz, Rich
- Re: [TLS] 0-RTT and Anti-Replay Roland Zink
- Re: [TLS] 0-RTT and Anti-Replay Martin Thomson
- Re: [TLS] 0-RTT and Anti-Replay Martin Thomson
- Re: [TLS] 0-RTT and Anti-Replay Viktor Dukhovni
- Re: [TLS] 0-RTT and Anti-Replay Roland Zink
- Re: [TLS] 0-RTT and Anti-Replay Viktor Dukhovni
- Re: [TLS] 0-RTT and Anti-Replay Roland Zink
- Re: [TLS] 0-RTT and Anti-Replay Colm MacCárthaigh
- Re: [TLS] 0-RTT and Anti-Replay Ilari Liusvaara
- Re: [TLS] 0-RTT and Anti-Replay Viktor Dukhovni
- Re: [TLS] 0-RTT and Anti-Replay Ilari Liusvaara
- Re: [TLS] 0-RTT and Anti-Replay Nico Williams
- Re: [TLS] 0-RTT and Anti-Replay Viktor Dukhovni
- Re: [TLS] 0-RTT and Anti-Replay Nico Williams
- Re: [TLS] 0-RTT and Anti-Replay Nico Williams
- Re: [TLS] 0-RTT and Anti-Replay Eric Rescorla
- Re: [TLS] 0-RTT and Anti-Replay Nico Williams
- Re: [TLS] 0-RTT and Anti-Replay Patrick McManus
- Re: [TLS] 0-RTT and Anti-Replay Dave Garrett
- Re: [TLS] 0-RTT and Anti-Replay Martin Thomson
- Re: [TLS] 0-RTT and Anti-Replay Eric Rescorla
- Re: [TLS] 0-RTT and Anti-Replay Eric Rescorla
- Re: [TLS] 0-RTT and Anti-Replay Nico Williams
- Re: [TLS] 0-RTT and Anti-Replay Ilari Liusvaara
- Re: [TLS] 0-RTT and Anti-Replay Watson Ladd
- Re: [TLS] 0-RTT and Anti-Replay Ilari Liusvaara
- [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Ilari Liusvaara
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Martin Thomson
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Ilari Liusvaara
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Martin Thomson
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Ilari Liusvaara
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Martin Thomson
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Ilari Liusvaara
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Martin Thomson
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Daniel Kahn Gillmor
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Ilari Liusvaara
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Ilari Liusvaara
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Martin Thomson
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Nico Williams
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Ilari Liusvaara
- Re: [TLS] 0-RTT (Was: Re: 0-RTT and Anti-Replay) Ilari Liusvaara