Re: SCRAM with channel binding downgrade attack - Mailing list pgsql-hackers

From Peter Eisentraut
Subject Re: SCRAM with channel binding downgrade attack
Date
Msg-id e418275f-586f-80a8-757a-5ab1792251fb@2ndquadrant.com
Whole thread Raw
In response to Re: SCRAM with channel binding downgrade attack  (Heikki Linnakangas <hlinnaka@iki.fi>)
Responses Re: SCRAM with channel binding downgrade attack
List pgsql-hackers
On 6/6/18 16:26, Heikki Linnakangas wrote:
> On 06/06/18 23:20, Peter Eisentraut wrote:
>> Aren't we attacking this on the wrong level?  We are here attempting to
>> prevent a SCRAM-SHA-256-PLUS -> SCRAM-SHA-256 downgrade, but we are not
>> preventing a SCRAM-SHA-256-PLUS -> anything-else downgrade.
> 
> The latest patch does prevent that, too. That was my complaint at 
> https://www.postgresql.org/message-id/030284cc-d1d6-ce88-b677-a814f61c1880%40iki.fi, 
> but it's been fixed now. (Or if you see a case where it still isn't, 
> that's a bug.)

OK, that would do, but we don't do anything about a SCRAM-SHA-256 ->
anything-else downgrade.  Instead of tying this to the channel binding,
should we tie it to the authentication type?

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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