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Re: ICMP Security Failures
> With IP-AH-ULP the router needs the key used to generate the AH. Otherwise
> the intervening router could only check, that there is an AH present, but
> could not check if AH is correct. Sharing the key with the router on the
> other hand degrades security, because the router can forge the AH of the host.
This is true. I don't see a general solution to this using the MD5
transforms.
Digital signature checking scares me.
> With IP-AH-AH-ULP the sending host could generate one AH with the key shared with
> the router and the other AH with a key shared with the other host.
This works fine with one security gateway. Road warrior to home base, say.
A typical case might involve two gateways: one at each end. I prove to my
gateway that I'm authorized to use the internet, I then prove to your gateway
that I'm authorized to pass through it, and then finally prove to your host
that
I am who I say I am.
This is independant of whether or not our gateways happen to implement a
tunnel to provide privacy as well.
But, it gets worse. Let's say I want to reserve bandwidth (I don't know much
about these efforts, btw) for a video conference. How many routers will have
to authenticate my packets before giving them preference? And will
authenticating these packets take so long as to make the bandwidth reservation
pointless?
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