Re: [tcpm] feedcback on tcp-secure-05

Fernando Gont wrote:
> At 15:04 13/07/2006, Anantha Ramaiah \(ananth\) wrote:
> 
>> > The doc should also indicate that preventing these attacks
>> > does NOT prevent ICMP attacks (and cite Gont's draft in this
>> > regard); it would be useful for the security considerations
>> > to address whether ICMPs should be blocked altogether and
>> > what the impact of that would be. Without such blocking, it's
>> > not clear what the utility of this solution would be.
>>
>> Ok.
> 
> I don't think tcpsecure should make any advice on what to do with ICMP.
> 
> Just make it clear that the introduced mechanisms do not prevent
> ICMP-based attacks against TCP, and provide a pointer to
> draft-ietf-tcpm-icmp-attacks-00.txt .
> 
> If you are going to make any other statement on this issue, state that
> the ICMP-based attacks are easier to perform, and thus should be
> mitigated (if not, it's ICMP that is the "weakest link in the chain").
> 
> You could also add that, fortunately, virtually every implementation has
> mitigated the ICMP attacks described in
> draft-ietf-tcpm-icmp-attacks-00.txt, by implementing most (if not all)
> the counter-measures described in that draft.

That last point doesn't obviate the issue that ICMP packets - even
validated by the mitigations in the draft above - are still easier to
spoof and can be spoofed by third parties than any of the attacks in
tcp-secure.

I.e., they remain the weakest link, and worrying about tcp-secure
protections is nonsensical by comparison, UNLESS ICMPs are entirely
blocked.

Joe

Re: [tcpm] feedcback on tcp-secure-05

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