Re: [saag] can an on-path attacker drop traffic?

Eric Rescorla <ekr@rtfm.com> Wed, 02 September 2020 16:45 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Wed, 2 Sep 2020 09:44:43 -0700
Message-ID: <CABcZeBNWf=8TU_tJK5rKyh_Veaa5L0jhV9qkvL7M-k-BaNYoRA@mail.gmail.com>
To: Michael Richardson <mcr+ietf@sandelman.ca>
Cc: IETF SAAG <saag@ietf.org>
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Subject: Re: [saag] can an on-path attacker drop traffic?
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QUIC ended up with a different taxonomy:
On-path
Off-path
Limited on-path (cannot delete)

-Ekr


https://datatracker.ietf.org/doc/html/draft-ietf-quic-transport-29#section-21.12.3.1


On Wed, Sep 2, 2020 at 9:28 AM Michael Richardson <mcr+ietf@sandelman.ca>
wrote:

>
> I think most of us agree that an "on-path" attacker can read traffic.
> They can problem inject traffic, and maybe even inject it in such a way
> that
> it beats the real traffic.
>
> I think that most of us can agree that an off-path attacker can not read
> traffic.
>
> So for instance, and on-path attacker can see the TCP SYN seq no or a DNS
> query ID, and therefore answer correctly.
> And off-path attacker has to depend upon implementation flaws to guess
> those
> values. (Which at one point were very common)
>
> A read-only on-path attacker that can read can be implemented with a
> MIRROR/SPAN port.
> Or as we learnt a few years ago with creative bending of fiber.
>
> A firewall or router is a potential on-path attacker, but it can also drop
> packets.
> What do we call this?
> This was historically called a MITM, and it implied all the attributes of
> on-path.  But it is unclear to me if MITM > on-path, or MITM == on-path.
>
> --
> Michael Richardson <mcr+IETF@sandelman.ca>ca>, Sandelman Software Works
>  -= IPv6 IoT consulting =-
>
>
>
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