InCommon Baseline TLS 1.2

[Peter Schober]

* Richard Frovarp via users <users at shibboleth.net> [2021-07-01 17:54]:
> > You're saying a modern Chrome or FF release will warn even if the
> > server in question also speaks an accaptable TLS version? (I've
> > certainly never encountered that myself.)
> 
> Yes, evergreen browsers will do this when the server negotiates TLSv1.0 or
> TLSv1.1 with the browser. In theory it is possible for a server that
> supports TLSv1.2 to actually negotiate TLSv1.[10]. Either the server is
> misconfigured, or through a downgrade attack.

Right. Assuming no attack is in currently happening and the server is
not misconfigured even newest browser releases will not sabotage the
connection to a server in any way if that server might /also/ be
offering older TLS versions. (At this time.)

> Connect to a RHEL5 box, and you will be treated to a pretty big
> warning in both Chrome and Firefox.

I'm guessing because the browser is modern and the OS is ancient?
(I.e., the inverse of what we're discussing here?)

> I think both projects planned on dumping TLSv1.0 and TLSv1.1 code
> from their projects last year [... ]
> So they aren't actively making the extra checks, but will warn very
> loudly or just fail when they stumble upon something less than
> TLSv1.2.

Modern browser releases, right. On misconfigured servers (or
rightfully during a downgrading attack).
Unless they sabotage connections as described above (which you're
saying they do not) I'm only concerned with older browser versions in
the context of whether and when to disable older TLS version. YMMV.

-peter