Re: stopping bots from phoning home

[mason () schmitt ca]

Paul,

Thanks for your suggestions.

While responding to your comments, it got me thinking.  So, I've decided
to share some of my other ideas for dealing with the problem of home
computer security from the perspective of an ISP.

There hasn't been a good constructive thread concerning the home user
problem in a while, so hopefully my follow up email to this one will spark
some interest.

<snip>

> Like the last time this surfaced, I'd recommend offering the customers a
> default deny option and see how many bite- if you can do per-user rules
> (and I don't know what sort of scale you're talking about- MSOs come in
> all sizes.) then you may get them to agree to it- I think the time is
> right for that.

It was a good suggestion then and it's a good one now, but my boss has
said that despite the obvious technical merit, he's not going for it. 
He's concerned about an increase in support costs and negative customer
experiences with people phoning in that forget/don't understand the
repercussions of their choice.  Or worse, leave us for the competition
without even phoning us, because they decide to use some new app that they
just downloaded and find that it doesn't work and their friend down the
street says, well it works fine on my dsl connection!

As well, the majority of support calls that we receive are from the very
people that need the protection most, but their use of the internet would
preclude a default deny ruleset on their modem.  The kids are on IM and
playing online games at all hours, the whole family participates in p2p
filesharing and the fact that their computers are loaded to the gills with
spyware suggests that they are spending time visiting the somewhat less
savoury places on the net.  The parents in these situations are most often
not very technically savvy and many don't really understand or supervise
what their kids are doing online.


> If you can get your customers to use an IRC proxy, great- it might be sort
> of interesting to look at doing a transparent proxy and just sending up a
> screen that asks for a specific response prior to continuing the
> connection- I'd be *really* interested in your results though, espeically
> with the newer IM clients that do IRC.

I have given this some thought and talked it over with others here and we
think that your variation on the original idea is an improvement.  Largely
due to the fact that popular IM clients, such as Trillian, that kind of
support IRC, wouldn't allow for authentication and some servers have a
limit on the number of connections from a single IP.  So, rather than run
all connections through a proxy, we thought that perhaps we could just
watch for IRC connections to be established (really easy with the
packetshaper and doesn't require sniffing).  When we see a connection
established, have a bot kick off that logs onto the server the connection
was made to and initiate a direct chat request to the  user that just
logged on.  The bot would ask a question and if it didn't get a response,
it would block IRC traffic for that IP and send an email to our ticket
system so that we know who is infected.

There's probably a less convoluted way of approaching this (if you have
one, let me know), but this is doable without having to do much
programming.

The big question is, whether it's worth the effort or not. I'm not sure. 
It increases the complexity of our network while only focusing on the
current fad in spyware/trojans/bots (what do we call these things now?) of
using IRC.  Currently there are bots (settled on bots), that once on the
host, will talk over http, p2p, or IM  in order to get their instructions.
 IRC is the current dominant method, but not the only one.

I'm more inclined to take a broader proactive approach, but could use some
guidance concerning some of my current half thought out ideas.  I'll send
these ideas along in my next email.

> You know, if we could get rid of the home user problem, all our lives
> would get easier...

Then there wouldn't be an internet and that would suck.  But, I know what
you mean...

> Personal firewalls that block outbound connections are a good thing- you
> might want to see if your marketing folks can do something akin to the
> AOL and DSL provier firewall packages- marketing always has money that
> techs don't...

Ha!  You wouldn't believe the support problems that we have with people
that choose to install firewalls that ask them to make choices.  I think
that having a firewall on the box that can see which program is trying to
connect is great! ...if there is a person interacting with it that
understands some basics.  When the person using the computer has no idea
what the little pop ups are talking about and doesn't really want to know,
they just blindly click ok, because clicking ok means that they are more
secure right?  We have had plenty of support calls where the customer is
angry that our mail server is down... when in reality, they clicked ok
when the window asked if they wanted to block pop3...

We do what we can to help out these people and sometimes that means having
them bring their pc in so that we can get a look at it.  Often we tell
them that they would be better off with a common home firewall.  The crazy
thing is that I know that many of the large ISPs (not sure if I should
name names or not) have it as part of their level1 tech support flow chart
to ask the customer to disable the firewall and leave it like that!  That
really chaps my ass.  If these big ISPs weren't so careless, I wouldn't
have so many problems... nor would the rest of the net for that matter. 
Oh well, finger pointing isn't going to get me anywhere.

--
Mason
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