On 04/11/2016 11:21, Gervase Markham wrote:
On 03/11/16 21:17, Jakob Bohm wrote:
Note that the GlobalSign SHA-1 intermediaries chain only to their old
SHA-1 root which is (I believe) not used for any SHA-256 certs, except
a cross-cert that signs their current SHA-256 root.
Nevertheless, it is still in Mozilla's trust store.
As it needs to be until the last general usage BR-compliant SHA-1
certificates issued in 2015 expire on or before 2016-12-31 23:59:60 UTC
So I suspect the intent of GlobalSign is that the old SHA-1 root should
loose its ServerAuth trust bit around 2017-01-01, reducing it to a
SHA-1-forever root trusted only by old SHA-1-only systems and maybe for
e-mail (because some non-Mozilla e-mail clients were very late to
supporting SHA-2 e-mail signatures).
If this were true, a) that's not good enough, as SHA-1 issuance has been
banned by the BRs since 2016-01-01, and b) they would have needed to
file a bug for this trust change long ago, and I can't find one.
I seem to recall the 3 certs were around new years (but on the wrong
side). The names suggest they are administratively (but not
technically) constrained to e-mail and similar certificates.
They really should have been technically constrained, but to do so now
would entail issuing at least one *new* SHA-1 cert with technical
constraints, reissuing the all the derived certs then revoking the 3
technically unconstrained intermediaries that were issued near the
start of 2016. Besides the administrative overhead of contacting all
certificate holders, this would stop the risk that collisions are used
to generate fake unrevokable certificates chaining to the
intermediaries, but add one more SHA-1 value signed by the root and
potentially attackable via 2nd preimage collision attacks.
But I do not represent GlobalSign, I am only making informed guesses
based on available public information.
Enjoy
Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S. https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark. Direct +45 31 13 16 10
This public discussion message is non-binding and may contain errors.
WiseMo - Remote Service Management for PCs, Phones and Embedded
_______________________________________________
dev-security-policy mailing list
dev-security-policy@lists.mozilla.org
https://lists.mozilla.org/listinfo/dev-security-policy
