Subject: Re: comments on nsec3-01

From: Alex Bligh <[email-masked]>
Date: Wed, 02 Mar 2005 16:21:07 +0000

--On 02 March 2005 16:33 +0100 Ted Lindgreen <[email-masked]> wrote:

>> > One of the many questions I have is what should be the default
>> > behavior in case you do not understand the new hash algorithm. Should
>> > you treat the answer as non secure?
>>
>> The answer is non secure, so it would be slightly insane to treat it any
>> other way.
>
> Shouldn't you be treating it as bogus? (Because it was meant to
> be secured, but you can't verify it).

It's no more bogus than an unsigned reply. It might be bogus, or it
might be a hash function you don't implement and be perfectly OK.

Alex

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From: Roy Arends <[email-masked]>
Date: Wed, 2 Mar 2005 17:50:47 +0100 (CET)

On Wed, 2 Mar 2005, Ted Lindgreen wrote:

> [Quoting Ben Laurie, on Mar  2, 16:18, in "Re: comments on nsec ..."]
>

I'm with Ted on this one. This is a degradation attack.

If the stripping of an NSEC3 record from the response can go undetected,
and meanwhile treating the other NSEC3 (with unknown hash) response as
unsigned, an attacker can degrade security.

Roy

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From: Ben Laurie <[email-masked]>
Date: Wed, 02 Mar 2005 17:25:36 +0000

> be secured, but you can't verify it).

But it isn't bogus, your validator is :-)

-- 
http://www.apache-ssl.org/ben.html       http://www.thebunker.net/

"There is no limit to what a man can do or how far he can go if he
doesn't mind who gets the credit." - Robert Woodruff

---

From: Ben Laurie <[email-masked]>
Date: Wed, 02 Mar 2005 17:27:16 +0000

> unsigned, an attacker can degrade security.

An attacker can "degrade security" in the same way by blocking the 
(understood) NSEC3 response and providing an unsigned response. This 
does not seem to me to be either interesting or preventable.

Cheers,

Ben.