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Bind before/after StartTLS (was: Re: authmeth-07 issues)
- To: ietf-ldapbis@OpenLDAP.org
- Subject: Bind before/after StartTLS (was: Re: authmeth-07 issues)
- From: Hallvard B Furuseth <firstname.lastname@example.org>
- Date: Wed, 10 Mar 2004 17:56:12 +0100
- In-reply-to: <OF6A0836FB.9A523361-ON86256E3C.0050A1FD-86256E3C.0050E10C@us.ibm.com>
- References: <email@example.com> <OF6A0836FB.9A523361-ON86256E3C.0050A1FD-86256E3C.0050E10C@us.ibm.com>
At Feb 16 2004, Roger Harrison wrote:
> With the fairly extensive reworking of the effect of Start TLS and
> TLS closure on the LDAP association state, I'm wondering how WG
> members view the need for these security considerations proposed by
> Hallvard. Your comments are greatly appreciated.
At Feb 16 2004, John McMeeking wrote:
> I don't think there is any need to add material to the Security
> Considerations section if the proposed changes to authmethod are made
> (your previous note on StartTLS and StopTLS).
I agree, but I just noticed that my second suggestion still
touches a problem:
> bind before startTLS is an insecure combination, and that an attacker
> also may insert a bind before a startTLS when the client expects to do
> anonymous operations with TLS.
Changing focus a bit, I suggest:
Since an attacker can sometimes inject a Bind operation before the
client can perform StartTLS, thus leaving the TLS-protected connection
with unexpected authentication, it can be prudent to Bind immediately
after StartTLS. Servers can enforce this by invalidating the
association after a successful StartTLS.
I don't quite like the wording, but that's the best I can come up with
at the moment.