Re: [TLS] external PSK identity enumeration Re: UPDATED Last Call: <draft-ietf-tls-tls13-24.txt> (The Transport Layer Security (TLS) Protocol Version 1.3) to Proposed Standard
Eric Rescorla <ekr@rtfm.com> Wed, 21 February 2018 14:22 UTC
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From: Eric Rescorla <ekr@rtfm.com>
Date: Wed, 21 Feb 2018 06:21:58 -0800
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To: Hubert Kario <hkario@redhat.com>
Cc: draft-ietf-tls-tls13@ietf.org, "<tls@ietf.org>" <tls@ietf.org>
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Subject: Re: [TLS] external PSK identity enumeration Re: UPDATED Last Call: <draft-ietf-tls-tls13-24.txt> (The Transport Layer Security (TLS) Protocol Version 1.3) to Proposed Standard
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On Wed, Feb 21, 2018 at 6:13 AM, Hubert Kario <hkario@redhat.com> wrote: > On Friday, 16 February 2018 18:06:41 CET The IESG wrote: > > The IESG has received a request from the Transport Layer Security WG > (tls) > > to consider the following document: - 'The Transport Layer Security (TLS) > > Protocol Version 1.3' > > <draft-ietf-tls-tls13-24.txt> as Proposed Standard > > The current draft states that if the server recognises an identity but is > unable to verify corresponding binder, it "MUST abort the handshake" > Which text are you referring to here? -Ekr at the same time, they "SHOULD select as single PSK and validate solely the > binder that corresponds to that PSK" > (Page 60, draft-ietf-tls-tls13-24). > > That allows for trivial enumeration of externally established identities - > the > attacker just needs to send to the server a list of identity guesses, with > random data as binders, if the server recognises any identity it will abort > connection, if it doesn't, it will continue to a non-PSK handshake. > > Behaviour like this is generally considered a vulnerability: > https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2003-0190 > https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-5229 > > I was wondering if the document shouldn't recommend ignoring any and all > identities for which binders do not verify to prevent this kind of attack. > -- > Regards, > Hubert Kario > Senior Quality Engineer, QE BaseOS Security team > Web: www.cz.redhat.com > Red Hat Czech s.r.o., Purkyňova 115, 612 00 Brno, Czech Republic > _______________________________________________ > TLS mailing list > TLS@ietf.org > https://www.ietf.org/mailman/listinfo/tls > >
- [TLS] UPDATED Last Call: <draft-ietf-tls-tls13-24… The IESG
- Re: [TLS] UPDATED Last Call: <draft-ietf-tls-tls1… Sean Turner
- [TLS] Future interoperability issues for HRR for … Hubert Kario
- Re: [TLS] Future interoperability issues for HRR … Benjamin Kaduk
- [TLS] external PSK identity enumeration Re: UPDAT… Hubert Kario
- Re: [TLS] Future interoperability issues for HRR … Eric Rescorla
- Re: [TLS] external PSK identity enumeration Re: U… Eric Rescorla
- Re: [TLS] external PSK identity enumeration Re: U… Hubert Kario
- Re: [TLS] external PSK identity enumeration Re: U… Eric Rescorla
- Re: [TLS] external PSK identity enumeration Re: U… Martin Thomson
- Re: [TLS] external PSK identity enumeration Re: U… Tony Putman
- Re: [TLS] external PSK identity enumeration Re: U… Hubert Kario
- Re: [TLS] external PSK identity enumeration Re: U… Hubert Kario