Re: [secdir] Review of draft-ietf-opsec-routing-protocols-crypto-issues-04

Sandra Murphy <Sandra.Murphy@sparta.com> Thu, 27 May 2010 19:38 UTC

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Date: Thu, 27 May 2010 15:34:37 -0400 (Eastern Daylight Time)
From: Sandra Murphy <Sandra.Murphy@sparta.com>
To: Vishwas Manral <vishwas@ipinfusion.com>
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Cc: manav.bhatia@alcatel-lucent.com, secdir@ietf.org, shares@nexthop.com, jjaeggli@checkpoint.com, 'Sam Hartman' <hartmans-ietf@mit.edu>
Subject: Re: [secdir] Review of draft-ietf-opsec-routing-protocols-crypto-issues-04
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On Thu, 27 May 2010, Vishwas Manral wrote:

> Hi Sandra,
>
> You may look at the draft I have added below (which I sent to the list but
> never posted)
>
> http://www.ietf.org/mail-archive/web/saag/current/msg01732.html
>
> It talks about the fact that there is another (like in your case a validly
> formatted protocol packet) check which can greatly reduce the effect of
> collision.
>
> Do let me know what you think about the same with respect to the draft at
> hand?

Well, until we figure out that a collision would lead to bad things 
happening, there's no real need to make a check to reduce the chance of a 
collision.

Which is why I asked.

There's a general concern that MD5 is showing weakness and so we're all 
happy to see movement away from MD5.  But the collision risk at the moment 
is not clear.

--Sandy

>
> Thanks,
> Vishwas
> -----Original Message-----
> From: Sandra Murphy [mailto:Sandra.Murphy@sparta.com]
> Sent: Thursday, May 27, 2010 11:56 AM
> To: Sam Hartman
> Cc: Nicolas Williams; shares@nexthop.com; jjaeggli@checkpoint.com;
> manav.bhatia@alcatel-lucent.com; vishwas@ipinfusion.com; secdir@ietf.org
> Subject: Re: [secdir] Review of
> draft-ietf-opsec-routing-protocols-crypto-issues-04
>
> I was discussing this just this morning with a colleague.
>
> The discussion of pre-image and collision points out that using collisions
> as an attack on a routing protocol is not that easy since routing
> protocols have format requirements - the attacker would have to find a
> collision that is also a validly formatted protocol packet.
>
> Even beyond that, if the authors can point to some damage an attacker
> could do in a routing protocol using a collision, that would be very
> interesting.
>
>
> --Sandy
>
> On Thu, 27 May 2010, Sam Hartman wrote:
>
>>>>>>> "Nicolas" == Nicolas Williams <Nicolas.Williams@oracle.com> writes:
>>
>>    Nicolas> I have reviewed this document as part of the security
>>    Nicolas> directorate's ongoing effort to review all IETF documents
>>    Nicolas> being processed by the IESG. Document editors and WG chairs
>>    Nicolas> should treat these comments just like any other last call
>>    Nicolas> comments.
>>
>>    Nicolas> This document aims to be an Informational RFC describing
>>    Nicolas> security problems with various routing protocols.
>>
>>    Nicolas> Aside from various spelling and other nits that the
>>    Nicolas> RFC-Editor can easily handle, I have no issues with this
>>    Nicolas> document and it is ready for publication.
>>
>> This document talks a lot about collision attacks against MD5 and then
>> draws the conclusion that MD5 should not be used as part of a MAC.  I
>> agree that it is prudent to provide alternatives to MD5.  However, I
>> think the current text implies that collision attacks against MD5 are
>> applicable to attacks against the use of MD5 in routing protocols.
>>
>> There is an introductory section that describes the difference between
>> pre image and collision attacks, but the rest of the document seems to
>> ignore the advice of that section.
>> _______________________________________________
>> secdir mailing list
>> secdir@ietf.org
>> https://www.ietf.org/mailman/listinfo/secdir
>>
>
>