FreeBSD Security Advisory FreeBSD-SA-14:19.tcp

[Leif Pedersen]

On Tue, Sep 16, 2014 at 8:49 AM, Mark Felder <feld at freebsd.org> wrote:

>
> How many AS are out there don't implement BCP38? Spoofing these days
> without MITM should be considered hard, and TCP even harder, no? I'd
> find it more believable that it's easier to hijack BGP than to target
> someone and successfully spoof TCP.
>
> Maybe I'm just naive and haven't seen this behavior in the wild during
> my time working at an ISP :-)
>
>
Between work and home, I have access to three internet connections from
different ISPs. None stop me from sourcing packets from arbitrary
addresses. For example, if I use "ifconfig xx0 alias 1.1.1.1/32; ping -S
1.1.1.1 <victim>" and use tcpdump on <victim>, I see the traffic with the
source address 1.1.1.1. I have no special arrangements; just typical
commodity service. So there are at least three ISPs serving my area that
don't prevent IP spoofing.


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