Subject: BFD Authentication

From: "Shahram Davari" <[email-masked]>
Date: Tue, 18 Aug 2009 14:48:59 -0700

Hi,

Reading through base draft, it seems that the suggested Authentication methods (password, MD5 and SHA1) are all very weak authentications and not really used any more. Is it too late to propose another simple but yet powerful Authentication such as GMAC?

Also since the Authentication Type is communicated in each packet does it mean that it is allowed to change Authentication type in the middle of a BFD session?

Thanks,
Shahram

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From: Dave Katz <[email-masked]>
Date: Tue, 18 Aug 2009 16:47:04 -0600

On Aug 18, 2009, at 3:48 PM, Shahram Davari wrote:

> Hi,
>
> Reading through base draft, it seems that the suggested  
> Authentication methods (password, MD5 and SHA1) are all very weak  
> authentications and not really used any more.

It seems like "very weak" is perhaps overstated, at least with regard  
to MD5 and SHA1, given the environment and the way it's applied.

> Is it too late to propose another simple but yet powerful  
> Authentication such as GMAC?

The spec is extensible;  please feel free to submit a proposal to the  
working group.

>
> Also since the Authentication Type is communicated in each packet  
> does it mean that it is allowed to change Authentication type in the  
> middle of a BFD session?

One could imagine such a thing, but it would require some form of out- 
of-band communication between the systems in order to establish it.   
One could imagine
switching authentication types in the same way that it is possible to  
switch key IDs.

---

From: Vishwas Manral <[email-masked]>
Date: Tue, 18 Aug 2009 16:01:41 -0700

Hi Shahram,

I raised issues on the security of BFD a lot of them got resolved in
the base draft itself.
www.ietf.org/mail-archive/web/rtg-bfd/current/msg00480.html
www.ietf.org/mail-archive/web/rtg-bfd/current/msg00488.html

Here is the document we wrote to address the other concern. It also
talks about a way of doing Key Rollovers like you mentioned.

http://tools.ietf.org/html/draft-bhatia-bfd-crypto-auth-00

Thanks,
Vishwas

On Tue, Aug 18, 2009 at 2:48 PM, Shahram Davari<[email-masked]> wrote:
> Hi,
>
> Reading through base draft, it seems that the suggested Authentication
> methods (password, MD5 and SHA1) are all very weak authentications and not
> really used any more. Is it too late to propose another simple but yet
> powerful Authentication such as GMAC?
>
> Also since the Authentication Type is communicated in each packet does it
> mean that it is allowed to change Authentication type in the middle of a BFD
> session?
>
> Thanks,
> Shahram

---

From: Tom Sanders <[email-masked]>
Date: Wed, 19 Aug 2009 09:42:07 +0530

> http://tools.ietf.org/html/draft-bhatia-bfd-crypto-auth-00

I remember WG discussing this draft some time back - what happened to
it? I skimmed through the draft (expired copy) and it seems that one
can support any authentication type using the proposed mechanism
(including GMAC based authentication) as its only the Key ID that's
passed in the messages.

One could rollover by using a new Key ID as alluded by Dave.

Any plans of resurrecting this work?

Toms.

---

From: Vishwas Manral <[email-masked]>
Date: Wed, 19 Aug 2009 07:29:23 -0700

Hi Tom,

As most of the effort in the WG iscurrently geared to get the first
level of drafts to the RFC stage, we have not pushed this any further.
However we do intend to keep the work and push the document to WG
status and further as we move forward .

Thanks,
Vishwas