Subject: [IPsec] New item for draft-ietf-ipsecme-failure-detection-02.xt

From: Tero Kivinen <[email-masked]>
Date: Wed, 10 Nov 2010 13:04:03 +0200

I started to think whether there are other possible attacks against
QCD and found one which might be possible if implementations do not
take care of it. The IKE SPIs are allocated during the IKE_SA_INIT.
The IKEv2 SA is really created during the IKE_AUTH. This means there
is a possibility that some implementation might consider IKE SA spis
still invalid before the IKE_AUTH finishes (for example another member
of the tight cluster might be updated with the IKE SA information only
after the IKE SA is ready). If attacker sees IKE_SA_INIT and grabs IKE
SAs from there and then sends IKE packet to that another member which
has not yet updated with this partial IKE SA that might trigger
QCD_TOKEN even when it should not.

This is not really big issue as in normal implementations already take
care of this by following the rule which says do not allow any other
exchanges before IKE_SA_INIT/IKE_AUTH finishes but this might happen
on certain cluster setups.
-- 
[email-masked]