Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds

Fernando Gont <> Fri, 01 November 2019 03:11 UTC

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To: Ted Lemon <>
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From: Fernando Gont <>
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Date: Fri, 1 Nov 2019 00:11:23 -0300
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Subject: Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds
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On 31/10/19 16:47, Ted Lemon wrote:
> On Oct 31, 2019, at 3:41 PM, Fernando Gont <
> <>> wrote:
>> As someone that has played a lot with ND-based DoS vectors, I should say
>> that you trust RAs, or you don't. If you do, all bets are off. ("sudo
>> apt-get install ipv6toolkit;man ra6" and you'll get examples of a bunch
>> of other DoS attacks that an attacker can perform).
> As an end user, I don’t have this experience.   If someone is spamming
> my network with RAs, I can find out who and disconnect them.   A DoS
> attack based on massive quantities of RAs is a lot different than an
> attack that shuts my network off with one multicast. 

The regular non-technical user has no clue about RAs or the like. So,
the network works, or it doesn't. Normally, if things do not work, thye
will unplug and re-plug the router, ironically triggering this problem
in many cases.

That said: There are plenty of one-plenty of one-packet DoS vectors in
SLAAC. e.g., sen an RA with a Cur Hop Limit of 0, send an RA that
advertises a default router with highes priority, or simply advertise
RIOs as ::/1 and 8000::/1, overriding default routers.

Any clueful attacker will use any that works, rather than sticking to a
specific one.

Fernando Gont
SI6 Networks
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492