Subject: Re: [multipathtcp] NATs and MPTCP security

From: Yoshifumi Nishida <[email-masked]>
Date: Wed, 1 Dec 2010 04:34:12 -0800

Hi Olivier,
I would like to know a potential risk to announce addresses that are
unreachable or correspond to different hosts.

Thanks,
--
Yoshifumi Nishida
[email-masked]

2010/11/22 Olivier Bonaventure <[email-masked]>:
> Hello,
>
>
> MPTCP has been designed with NATs and middleboxes in mind. However when
> considering security, these devices cause annoying problems. To
> illustrate these problems, it is interesting to remember which fields of
> the IP and TCP headers can be modified by middleboxes :
>
> - source IP address
> - destination IP address
> - source port
> - destination port
> - sequence number
> - acknowledgement number
> - window
>
> This implies that in practice a security mechanism for MPTCP can only
> rely on information that is exchanged inside TCP options as all the
> other fieds of the TCP header are 'mutable'. This is important in
> comparison with shim6 or sctp for example where middleboxes are not as
> important.
>
> This also implies that we have to be careful with the ADD_ADDR and
> REMOVE_ADDR options as when one of the communicating hosts is behind a
> NAT we can advertise information about addresses that are either
> unreachable or correspond to different hosts (e.g. a client using an
> RFC1918 address behind a NAT and a server that resides in a LAN attached
> to another LAN using the same private IP addresses as those of the client).
>
>
>
> Olivier
> --
> INL, ICTEAM, UCLouvain, Belgium, http://inl.info.ucl.ac.be
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