Re: [TLS] NULL cipher to become a MUST NOT in UTA BCP
Viktor Dukhovni <ietf-dane@dukhovni.org> Tue, 02 September 2014 15:23 UTC
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Date: Tue, 02 Sep 2014 15:23:08 +0000
From: Viktor Dukhovni <ietf-dane@dukhovni.org>
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Subject: Re: [TLS] NULL cipher to become a MUST NOT in UTA BCP
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On Mon, Sep 01, 2014 at 04:58:13PM +0200, Ralph Holz wrote: > Practices "Recommendations for Secure Use of TLS and DTLS" > > http://tools.ietf.org/html/draft-ietf-uta-tls-bcp-02 > > => "Implementations MUST NOT negotiate the NULL cipher suites" > > This may lead to implementations dropping NULL (or making it hard to > enable). > > My personal take as one of the authors of the BCP is that the UTA WG > should process UNLESS someone has a use case that is relevant on the > same scale, or thinks the above statement does not hold in general. Postfix supports authenticated NULL ciphers for communication between an MTA and local (127.0.0.1 or ::1) LMTP server. Encrypting local IPC is just a waste of CPU. Yes, this is a specialized use-case. This can also be useful for access-controlled hand-off between reverse HTTP proxies, and web applications that support client certificates. These are sometimes used to implement GSSAPI SPNEGO support in front of application that don't support GSSAPI. The application is configured to listen on 127.0.0.1, but is then vulnerable to impersonation attacks from anything running on the host. With authenticated NULL ciphers, the connection can be restricted to just the front-end reverse proxy. -- Viktor.
- [TLS] NULL cipher to become a MUST NOT in UTA BCP Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Blumenthal, Uri - 0558 - MITLL
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Viktor Dukhovni
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Paul Hoffman
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Salz, Rich
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Viktor Dukhovni
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Blumenthal, Uri - 0558 - MITLL
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Viktor Dukhovni
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Viktor Dukhovni
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Paul Lambert
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Bodo Moeller
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Blumenthal, Uri - 0558 - MITLL
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Nico Williams
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Nikos Mavrogiannopoulos
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Yutaka OIWA
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Blumenthal, Uri - 0558 - MITLL
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Viktor Dukhovni
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Blumenthal, Uri - 0668 - MITLL
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Viktor Dukhovni
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Geoffrey Keating
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Blumenthal, Uri - 0668 - MITLL
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Nico Williams
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Nico Williams
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Nico Williams
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Blumenthal, Uri - 0668 - MITLL
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Blumenthal, Uri - 0558 - MITLL
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Yutaka OIWA
- [TLS] uta-tls-bcp-02 thoughts (was: NULL cipher t… Viktor Dukhovni
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Bodo Moeller
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Yutaka OIWA
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Nico Williams
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Blumenthal, Uri - 0558 - MITLL
- Re: [TLS] uta-tls-bcp-02 thoughts (was: NULL ciph… Blumenthal, Uri - 0558 - MITLL
- Re: [TLS] uta-tls-bcp-02 thoughts (was: NULL ciph… Nico Williams
- Re: [TLS] uta-tls-bcp-02 thoughts (was: NULL ciph… Blumenthal, Uri - 0558 - MITLL
- Re: [TLS] uta-tls-bcp-02 thoughts Ralph Holz
- Re: [TLS] uta-tls-bcp-02 thoughts Blumenthal, Uri - 0558 - MITLL
- Re: [TLS] uta-tls-bcp-02 thoughts Ralph Holz
- Re: [TLS] uta-tls-bcp-02 thoughts (was: NULL ciph… Barry Leiba
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Bill Frantz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Daniel Kahn Gillmor
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Bodo Moeller
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Manuel Pégourié-Gonnard
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Viktor Dukhovni
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Manuel Pégourié-Gonnard
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ilari Liusvaara
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Nico Williams
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Blumenthal, Uri - 0668 - MITLL
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Ralph Holz
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Bodo Moeller
- Re: [TLS] NULL cipher to become a MUST NOT in UTA… Viktor Dukhovni