Re: [v6ops] [EXTERNAL] Re: Improving ND security

Fernando Gont <fernando@gont.com.ar> Mon, 03 August 2020 18:53 UTC

Return-Path: <fernando@gont.com.ar>
X-Original-To: v6ops@ietfa.amsl.com
Delivered-To: v6ops@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 83B3B3A0A3D; Mon, 3 Aug 2020 11:53:11 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.937
X-Spam-Level:
X-Spam-Status: No, score=-0.937 tagged_above=-999 required=5 tests=[NICE_REPLY_A=-0.949, SPF_HELO_NONE=0.001, T_SPF_PERMERROR=0.01, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UR2zKUFZdYzJ; Mon, 3 Aug 2020 11:53:10 -0700 (PDT)
Received: from fgont.go6lab.si (fgont.go6lab.si [91.239.96.14]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 160DE3A0A3C; Mon, 3 Aug 2020 11:53:06 -0700 (PDT)
Received: from [IPv6:2800:810:464:1f7:50ff:5211:f841:308c] (unknown [IPv6:2800:810:464:1f7:50ff:5211:f841:308c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by fgont.go6lab.si (Postfix) with ESMTPSA id EB11F28028C; Mon, 3 Aug 2020 18:53:02 +0000 (UTC)
To: "Templin (US), Fred L" <Fred.L.Templin@boeing.com>, "Pascal Thubert (pthubert)" <pthubert@cisco.com>
Cc: v6ops list <v6ops@ietf.org>, 6man <ipv6@ietf.org>
References: <d5c245f216c3409f826f8132e532a882@boeing.com> <860E06E2-2650-4AAE-AD33-D4D12B0290DC@fugue.com> <b66ce3d9c75d4a39b5336dcdf9929411@boeing.com> <0DDEBA6C-3933-40FC-BB9C-33FA59DC9D76@cisco.com> <4907a159683346789bef5c495f03f95d@boeing.com> <b5043a5446914cb5b12ed76401359c7e@boeing.com> <3978163f-8815-1bd4-0fda-d84df9cbe684@gont.com.ar> <6b0d6c0a790b46c893b0ff3051599fb4@boeing.com>
From: Fernando Gont <fernando@gont.com.ar>
Message-ID: <85d89256-a495-d779-2c7c-2573bfae36c5@gont.com.ar>
Date: Mon, 03 Aug 2020 15:52:35 -0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1
MIME-Version: 1.0
In-Reply-To: <6b0d6c0a790b46c893b0ff3051599fb4@boeing.com>
Content-Type: text/plain; charset="utf-8"; format="flowed"
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/v6ops/L8kSliV45YHPL_55gIJlwTTjJA4>
Subject: Re: [v6ops] [EXTERNAL] Re: Improving ND security
X-BeenThere: v6ops@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: v6ops discussion list <v6ops.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/v6ops>, <mailto:v6ops-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/v6ops/>
List-Post: <mailto:v6ops@ietf.org>
List-Help: <mailto:v6ops-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/v6ops>, <mailto:v6ops-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 03 Aug 2020 18:53:12 -0000

Hi, Fred,

On 3/8/20 13:45, Templin (US), Fred L wrote:
[....]
>> This message was sent from outside of Boeing. Please do not click links or open attachments unless you recognize the sender and
>> know that the content is safe.
>> On 3/8/20 11:22, Templin (US), Fred L wrote:
>>> Here’s another think about SEND. RFC3971 SEND says that it works in
>>> conjunction with Cryptographically Generated addresses (CGA) per RFC3972. But, CGAs are
>>> cumbersome to work with as the source and destination addresses of IPv6 packets,
>>> and SEND hints that it can be used without CGA but does not tell how to do so.
>>
>> Of the top of my head, CGAs are a core part of send.
> 
> That is fine; we can accommodate CGAs in OMNI, cumbersome as they are.
> I have this on my TODO list for after the adoption call.

Why "cumbersome"?



>>> But then, RFC4380 offers a “poor-man’s” alternative to SEND/CGA. It
>>> places a message authentication code in the encapsulation headers of IPv6 ND messages so
>>> that the messages can pass a rudimentary authentication check.
>>
>> You mean the Teredo spec? If so, I don't think it includes any sort of
>> poor-man's SEND-CGA.
> 
> It provides for message authentication, 

But what's special about SEND/CGAs is that they tie the address to a key...


> and it is widely-deployed which suggests
> to me that the vendors who support it believe it is secure. 

I'm sure others probably know better, but... I think Teredo is mostly MS 
+ Miredo. (when it comes to implementation)

And Re: deployment, IIRC Teredo has been phased out.



> So, if it is secure enough for RFC4380, then shouldn't it also be secure enough for OMNI?

I believe Auth in Teredo is a totally different thing from SEND/CGAs.

Regarding OMIN, I Haven read the draft/spec, yet...




>>> So someone with
>>> security experience please help me out here – is RFC4380 authentication an acceptably
>>> secure  replacement for SEND/CGA that might be easier to work with and less
>>> cumbersome?
>>
>> Nope. Tee point of CGAs is that they allow you to prove address
>> ownership. There's nothing in RFC4380 that provides the same or similar
>> functionality.
> 
> Why do we have to prove address ownership

Well, that's one of the goals of SEND/CGAs. :-)


> and use a whacky address format like CGA?

The *address format* is not really whacky. At the end of the day, it's a 
random number, with the specific property that it's part of the hash of 
a public key.

looking at a CGA, you probably wouldn't be able to tell CGA from RFC7217.



> There is nothing in the OMNI spec that needs or wants CGAs in any fashion
> unless they are absolutely required for security. Isn't it enough to prove message
> authentication using the mechanisms of RFC4380 without having to accommodate
> the excess baggage of CGAs??

Both are different things.

One thing is to authenticate the contents of a message. And a different 
one is to be able to tell that one specific host is "authorized" to use 
one specific address...


-- 
Fernando Gont
e-mail: fernando@gont.com.ar || fgont@si6networks.com
PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1