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Message-ID: <1a18d4d5bd1ff610cde84055a87a19e6@mail.insa-lyon.fr>
Date: Sat, 07 May 2011 15:05:04 +0200
From: Gervais Arthur <arthur.gervais@...a-lyon.fr>
To: <netdev@...r.kernel.org>
Subject: Re: Fwd: PROBLEM: IPv6 Duplicate Address Detection with non RFC-conform
ICMPv6 packets
I made a small mistake in the proof of concept code.
Please find attached the corrected version (2 lines are modified)
Best regards,
Arthur Gervais
On 05/07/2011 02:55 PM, Jan Ceuleers wrote:
> The networking folks are on netdev
>
> -------- Original Message --------
> Subject: PROBLEM: IPv6 Duplicate Address Detection with non RFC-conform
> ICMPv6 packets
> Date: Thu, 05 May 2011 11:52:05 +0200
> From: Gervais Arthur <arthur.gervais@...a-lyon.fr>
> To: <linux-kernel@...r.kernel.org>
> CC: <arthur.gervais@...a-lyon.fr>
>
> [1.] One line summary of the problem:
>
> A specially crafted Ethernet ICMPv6 packet which is not conform to the
> RFC can perform a IPv6 Duplicate Address Detection Failure.
>
> [2.] Full description of the problem/report:
>
> If a new IPv6 node joins the local area network, the new node sends an
> ICMPv6 Neighbor Solicitation packet in order to check if the
> self-generated local-link IPv6 address already occupied is.
>
> An attacker can answer to this Neighbor Solicitation packet with an
> ICMPv6 Neighbor Advertisement packet, so that the new IPv6 node is not
> able to associate the just generated IPv6 address.
> -- This problem is well known and IPv6 related.
>
> The new problem is that the attacker can modify the Ethernet Neighbor
> Advertisement packets, so that they are not RFC conform and so that it
> is even more difficult to detect the attacker.
>
> If an attacker sends the following packet, duplicate address detection
> fails on Linux:
>
> Ethernet Layer: Victim MAC --> Victim MAC
> IPv6 Layer: fe80::200:edff:feXX:XXXX --> ff02::1
> ICMPv6
> Type 136 (Neighbor Advertisement)
> Target: fe80::200:edff:feXX:XXXX
> ICMPv6 Option
> Type 2 (Target link-layer address) Victim MAC
>
> Please find attached a drawing and a proof of concept.
>
> [3.] Keywords (i.e., modules, networking, kernel):
>
> Network, IPv6, Duplicate Address Detection
>
> [4.] Kernel version (from /proc/version):
>
> Latest tested:
> Linux version 2.6.35-22-generic (buildd@...hera) (gcc version 4.4.5
> (Ubuntu/Linaro 4.4.4-14ubuntu4) ) #33-Ubuntu SMP Sun Sep 19 20:34:50 UTC
> 2010
> (and before most probably)
>
> [6.] A small shell script or example program which triggers the
> problem (if possible)
>
> Please find attached a python script demonstrating the problem.
>
> [X.] Other notes, patches, fixes, workarounds:
>
> The Linux Kernel should not accept incoming Ethernet packets originating
> from an internal Ethernet card (identified by the MAC address)
>
View attachment "dad-dos_special.py" of type "text/x-python" (974 bytes)
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