From: vnend@phoenix.Princeton.EDU (D. W. James)
Subject: Re: Sendsys police
Originator: news@ernie.Princeton.EDU
Organization: Princeton University
Date: Wed, 8 Apr 1992 22:20:31 GMT

In article <1992Apr8.165406.26227@mp.cs.niu.edu> rickert@mp.cs.niu.edu (Neil Rickert) writes:
)In article <1992Apr8.145433.9988@cubmol.bio.columbia.edu> dan@cubmol.bio.columbia.edu (Daniel Zabetakis) writes:
)>In article <1992Apr7.230922.918@mp.cs.niu.edu> rickert@mp.cs.niu.edu (Neil Rickert) writes:
)>>In article <1992Apr7.194830.19599@Princeton.EDU> vnend@phoenix.Princeton.EDU (D. W. James) writes:

)>>>Set up a robot mailer on uunet.

)>> Add one more problem:

)>>	Unfortunately backbones site B has been down for several days, due
)>>	to a hardware problem.  Its authentication message is still sitting

	See the reference to "conscientious news admins" as the folks running
it.  That's one fix.  An other is to have to program poll UUNET on restart
to see if it has the latest version of the code.  That is both doable and
automatic.  It simply doesn't start cancelling messages until it hears back
from UUNET.

	Next...

	 
)>loose interest will just fade away. The good part is that there wouldn't need
)>to be many sites running sys_police.
 
) Wrong.  There WOULD need to be many sites running sendsys police.  With only
)a few sites, any 'sendsys' forger would merely list those sites in the initial
)"Path:" thereby ensuring that they never see the article.  You either need
)enough sites that it is inconceivable that a forger would correctly discover
)and enter all in "Path:", or you need enough sites that avoiding them would
)seriously disrupt article propogation.  With the continued spread of nntp it is
)becoming very hard to seriously disrupt propogation.
 
	Yes and no.  Sure, you can write a path that avoids the backbone sites,
lets keep it reasonable and say 25-50 sites.  That's one hell of a path line,
and it is going to slow down the spread of the article more than somewhat.
It is quite likely that the site under attack will be able to get a cancel out
before the whole flood hits.

	In any event, this alone is not a reason not to try to impliment the
idea.  Sure, it isn't perfect.  But it is infinately better than nothing,
and requires a lot of knowledge on the part of the forger.  I think that the
reason we see sysbombs now is because it is so easy.  If it weren't, I think
that there would be a lot fewer of them, not that we have a lot of them now
anyway.  Putting a fix like this in place would probably discourage the
random idiot that does them anyway, and a determined idiot would need to
give us a lot of paths to pin them down with trying to map out all the sites.

	I think that the best complaint so far about the idea is one that is
close to a disad that I thought of last night after I sent the note.  It 
occurred to me that I was proposing bringing back the backbone cabal.  That,
and investing yet another bit of work to a single site (UUNET) are definately
disadvantages.  I'm not convinced that they are intolerable ones.

	The first, the return of the Backbone Cabal, seems to be nearly
unavoidable if we want something to stop sysbombs.  We can't force everyone
to upgrade their software, so we have to rely on sites that will.

	The second we can try to address in software, by having more than
one key site, or by having a set of backup sys.cop sites.  If your mail
to UUNET isn't responded to in a reasonable amount of time, try backup 
number one, etc..  Being wildly optimistic, I'll say that we should only
need about 5 sites to make that work.  Say, something like:

     1  36.04   uunet
     2  24.50   zaphod.mps.ohio-state.edu
     3  18.80   wupost
     4  15.02   usc
     5  14.41   cs.utexas.edu
     6  14.02   mcsun
    32   4.44   munnari.oz.au

and perhaps unido and/or ira.uka.de.  We could probably drop either 
zaphod or wupost, and one of either usc or cs.utexas.edu.  Munnari and
mcsun so that they can be caught before they make the big jump into
the USA, where most of the sites still are.

	Unfortunately, the peer software makes things more complicated,
which is a disadvantage in and of itself.  But it is still workable.




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