Re: Yahoo outage summary

["Steven M. Bellovin" <smb () cs columbia edu>]

On Sun, 8 Jul 2007 19:51:04 -0400 (EDT)
Sean Donelan <sean () donelan com> wrote:

> On Sun, 8 Jul 2007, Steven M. Bellovin wrote:
> > > I put up a diary at the Storm Center
> > > (http://isc.sans.org/diary.html?storyid=3112) that summarizes what
> > > we know about the Yahoo outage on Friday.  If anybody has any
> > > additional info they want to share or comments about the write-up
> > > please let me know.
> > In other words, it was yet another BGP screw-up that secured routing
> > could have prevented.
>
> Or using route registeries and filters, or any of the other dozen
> ideas suggested over the last decade.
>
> > Any clue about the root cause, i.e., malice or accident?
>
> Does it matter?  You are screwed either way.
It tells us what we need to do to prevent such things from happening in
the future.  For example, most misconfigurations could be blocked if
all routers matched prefixes against originating ASNs, and it doesn't
matter much if the assertion is digitally signed or not -- all that
matters is that the check is done against some authoritative database
run, say, by the RIRs.  (No, that's not quite the right solution, but
it serves to illustrate my point.)  That's completely inadequate
against an attacker.


                --Steve Bellovin, http://www.cs.columbia.edu/~smb