Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1.1"
Viktor Dukhovni <ietf-dane@dukhovni.org> Fri, 26 April 2019 01:30 UTC
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Subject: Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1.1"
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> On Apr 12, 2019, at 7:28 PM, Christopher Wood <caw@heapingbits.net> wrote: > > This is the working group last call for the "Deprecating TLSv1.0 and TLSv1.1” draft available at: > > https://datatracker.ietf.org/doc/draft-ietf-tls-oldversions-deprecate/ > > Please review the document and send your comments to the list by April 26, 2019. My concern is whether the time is yet nigh for TLS 1.0 to be disabled in opportunistic TLS in SMTP, or whether TLS 1.0 remains sufficiently common to cause deprecation to do more harm than good via unnecessary downgrades to cleartext. I don't have survey numbers for SMTP TLS protocol versions across MTAs generally to shed light on this, perhaps someone does. What I do have is numbers for those MTAs (not a representative sample) that have DANE TLSA records (so presumably a greater focus on security). The observed version frequencies are approximately: TLS 1.0: 1% TLS 1.1: 0% TLS 1.2: 87% TLS 1.3: 12% essentially regardless of whether I deduplicate by name, IP or name and IP. The respective sample sizes are 5435, 6938 and 7959. So if a DANE-enabled sender were to disable TLS 1.0 today, approximately 1% of the destination MX hosts would be broken and need remediation. These handle just of 189 mostly small SOHO domains out of the ~1.1 million total DANE SMTP domains, but four handle enough email to show up on the Gmail SMTP transparency report: tu-darmstadt.de t-2.net t-2.com t-2.si So on the whole, the draft should proceed, but some caution may be appropriate outside the browser space, before operators start switching off TLS 1.0 support. I don't see an operational considerations section. Nor much discussion of "less mainstream" (than Web browser) TLS application protocols. Would a few words of caution be appropriate, or is it expected that by the time the RFC starts to change operator behaviour the "market share" of TLS 1.0 will be substantially lower than I see today even with SMTP, XMPP, NTTP and the like. [ I would speculate that TLS 1.0's share is noticeably higher among MTAs generally than among the bleeding-edge MTAs that have published DANE TLSA RRs. ] -- Viktor.
- [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1.1" Christopher Wood
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Watson Ladd
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Thomson
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… John Mattsson
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Maarten Aertsen (NCSC-NL)
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Stephen Farrell
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Gary Gapinski
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Daniel Migault
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Viktor Dukhovni
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Loganaden Velvindron
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Hubert Kario
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Töma Gavrichenkov
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Salz, Rich
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Viktor Dukhovni
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Roland Zink
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Thomson
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Christopher Wood
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Viktor Dukhovni
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Rex
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Töma Gavrichenkov
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Thomson
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Hubert Kario
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Rex
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Hubert Kario
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Peter Gutmann
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Benjamin Kaduk
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Peter Gutmann
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Viktor Dukhovni
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Eric Rescorla
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Peter Gutmann
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Thomson
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Hubert Kario
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Hubert Kario
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Töma Gavrichenkov
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Benjamin Kaduk
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Blumenthal, Uri - 0553 - MITLL
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Viktor Dukhovni
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Viktor Dukhovni
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… David Benjamin
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Rex
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Peter Gutmann
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Hubert Kario
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Rex
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Peter Gutmann
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Thomson
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Hubert Kario
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Rex
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Peter Gutmann
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Hubert Kario
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Rex
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… David Benjamin
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Kathleen Moriarty
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Hubert Kario
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Rex
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Peter Gutmann
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Christopher Wood
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Martin Rex
- Re: [TLS] WGLC for "Deprecating TLSv1.0 and TLSv1… Peter Gutmann