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Re: [v6ops] Same interface ID under several prefixes

Fernando Gont <fernando@gont.com.ar> Fri, 17 June 2022 22:20 UTC

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To: Brian E Carpenter <brian.e.carpenter@gmail.com>, Fernando Gont <fgont@si6networks.com>, IPv6 Operations <v6ops@ietf.org>
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From: Fernando Gont <fernando@gont.com.ar>
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Subject: Re: [v6ops] Same interface ID under several prefixes
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On 17/6/22 17:51, Brian E Carpenter wrote:
[...]
>>
>> I assume they don't claim to implement RFC7217. -- If they did, then
>> yes, it would be fair to call that a bug. :-)
> 
> Right, it would be fairer to call it a potential privacy vulnerability
> (discover one address, get another one free of charge).

Indeed, their mechanism allows for host-tracking: i.e., once you know 
the token, you can predict what's the address that that node would 
configured if it connected to a given network.


> I don't regard
> it as a very serious problem that an outsider can learn my ULA or
> LLA.

The biggest problem is that once the attacker learns your token, e.g., 
he can test whether you're connected to e.g. the IETF conference network 
by e.g. pinging PREFIX::your_token.



> Kudos to MS, anyway, for having moved to pseudo-random IIDs very early,
> before RFC7217 in fact.

Yes, that was the point I was trying to make!

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

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