Firewall Wizards mailing list archives

Re: The home user problem returns


From: Mason Schmitt <mason () schmitt ca>
Date: Tue, 13 Sep 2005 15:34:23 -0700

When enough people choose to smoke, they are placing an unnecessary
burden on the public medical system, thereby degrading it for everyone
else.


Are they?  Will they really?  Afterall, considering the above, they are
not likely to live as long and thus not going to be within the system as
long term as the non-smokers.

Are you certain of this, or is it just another version of overhype in
this current time and space?  Afterall, think about it a momnet, if I
draw smoke directly into my lungs, and exhale and then you breath in a
small fraction of what residule smoke is left, it is really more of a
health issue for you in a secondary fashion then it was for me in the
first intake?

I should have known better than to bring as touchy an example as this in
as an analogy...

You know what, I don't honestly know.  I have seen reference to so many
studies, so much backlash against tobacco companies, (I also really
liked the movie "The Insider"...), that I have a hard time thinking it's
not true, but I really didn't come here to debate smoking.  I'm sorry I
inadvertently pulled attention away from the topic at hand.


...snipped out my original description of my bot problem

That sure seems like a long way about trying to limit the exposures that
got and get you into the fixes you find in your ISP technical position,
so, let me ask here again, would it not be simpler, and likely go pretty
much untocinted to the vast majority of your users to just lont allow
ports 135-139, 455, and 500 and the rest of the windws specifics from
leaving your periniters and even actually eliminate it on your
braodcasts within?

In a word... no.  We have had all those filters in place for a long
time.  They don't do dick when faced with a bot that comes in via a p2p
download or IM download that then sets up shop and decides to go after
your relay rather than trying to do direct-to-mx zombie spamming.

The bot problem is an insidious one and they are getting smarter.

  Seems that would be far less work and likely with
the ingress and egress filtering eliminate 90% of the issues that hit
you and your user base, would it not?

It's not even remotely close to 90% unfortunately.

 and certainly without the support
overhead of the vast majority of the plans and solutions you are trying
to impliment, yes?


I'm going the extra distance (and I imagine all ISPs are going to be in
a similar boat) because I'm forced to and because I know that if I don't
start the hardening process now, I'm going to get burnt badly and have
to scramble for a solution later.


My question to the rest of the list remains:  how much would an ISP
suffer if they invoked such policies?

Not at all.  It's a great start to improving the situation - something
that all ISPs should be undertaking asap.  It would sure help cut down
on the amount of worm traffic on the net.  Take a look at dshield
sometime for an idea of how much those simple rules would help.

 and invoked such policies with
the hitting those that request to be allowed to avoid those limitaions
with a service expansion and extra hit from the pocketbook?

That's unlikely to happen.  Why would someone pay extra for such a thing?

Rather then
give it all away under the basic pricing infrastructure, you make those
that wish for the "addon risks" pay for it.

Again, all the things I'm talking about have little to no negative
impact on customers.  In fact, here's the current list from our router
(my boss cleared this).  There's no harm in disclosing this, because
anyone that wants to go after our customers can use any of the other
thousands of ports that are open - these are just to block the common
automated crap.

# Microsoft stuff
tcp     42                  # WINS
udp     42
tcp     135                 # epmap (blaster worm)
udp     135
tcp     137:139             # SMB
udp     137:139
tcp     445                 # win2k SMB
udp     445                 # not really necessary, but...
tcp     1433:1434           # ms-sql
udp     1433:1434
udp     1900                # UPnP service announcement traffic

# Worms/Trojans
tcp     1022:1023           # New Sasser Variant
tcp     2745                # Bagel/beagle backdoor
udp     2745
tcp     3127                # Mydoom
tcp     3129:3199           # Mydoom
udp     3127:3199
tcp     5554                # Sasser ftp
tcp     6129                # Dameware
tcp     9996                # Sasser backdoor
tcp     9898                # Dabber backdoor
tcp     27374               # some trojans

--
Mason
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