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[ISN] Attack on Feds: It Came From Within


SEPTEMBER 23, 2002
My security team was recently asked to help reduce costs by
consolidating after-hours security and IT support services. We had
been charging a nightly fee for round-the-clock on-call support, but
the company reasons that it's cheaper to consolidate all first-line
support to the on-call IT team that supports our applications.  I
trained the on-call team, covering the most common problems and what
to do if there's a situation they can't handle. My security team now
offers second-line support.

The alerting system is well tuned, and we don't get many after-hours
alarms, so I doubted we'd be called often. I was wrong.

At 3 a.m. on the first night the IT team took over, I received a call
from a rather worried on-call guy who had been paged with an "ISS"  
alert. He didn't know that ISS just stands for Internet Security
Systems Inc., the Atlanta-based vendor of our intrusion-detection

One of the many things we can detect is probes sent from ISS's
Internet Scanner software. The scanner lets administrators check their
networks for vulnerabilities, but attackers can also misuse it to map
our networks and identify weaknesses. ISS tries to prevent this by
using a complicated licensing process that limits the IP addresses
each tool can attack. It also sends some special packets at the
beginning of each scan, including the license key, the user name, and
the host and domain of the scanning machine. That way, if someone uses
the tool to scan a network they don't own, the product will announce
who they are.

We monitor for these packets in case somebody finds a way, using
network address translation perhaps, to trick the scanner into
thinking it's probing a local machine when in fact it's scanning us.

More worrisome is that, as with other digital rights management
systems, hackers claim to have broken ISS's license key system. In
fact, key-generation software can be found on the Web to make keys for
any network.

The fake license keys these tools generate typically have an ID of
1234. So even if the special packets contain the hacked ID, you have
very little to go on. We could also expect the attacker's IP address
to be faked.

The normal response to an ISS alert, we told the new support team, is
to trace down the source of the attack via the America Registry for
Internet Numbers (ARIN) Web site at www.arin.net and notify the
attacker's Internet service provider. We even have standard forms for
those submissions. We don't really expect the ISP to do anything, but
at least we try.

Internal Attack

But the detail that worried the front-line support chap, and that made
me snap awake at that awful hour, was the source of the attack: It
came from within our own network.

Maybe someone we'd hired was a bit of a hacker. Or maybe the system
had it wrong and the attacker was actually the target.

I asked the support technician for the target address of the probes.  
It was the IP address, which seemed rather odd. The address
range 10.x.x.x is reserved so companies can use it internally, as we
do. So perhaps this was a typo? Who was 11.x.x.x? After a quick check
of ARIN, my blood ran cold. The results read:

DOD Intel Information Systems (NET-DODIIS)

Defense Intelligence Agency

Washington, D.C.

We had detected an attack against the DIA, the heart of the U.S.  
intelligence services, that came from our own network - and I doubted
that we were the only people to spot this. No doubt somewhere in
Washington someone was also being woken to respond.

Whoops. We had to work out what was going on before men in trench
coats and dark glasses arrived. I took control of the call and began
searching for the internal machine.

I traced the machine to one of our Unix server clusters. It seemed to
be the one running our enterprise monitoring system (EMS). That didn't
make sense - ISS stopped making Unix versions of Internet Scanner a
long time ago. If a hacker could get hold of a license generator, why
would he make keys for an old version? The Unix version of Internet
Scanner was five years old, so the problems it might look for would
have been fixed by now, making it useless.

The Mix-up

Then a few pieces fell into place. The EMS pings every interface on
every router we have to make sure each is responding correctly, and
the ISS special packets use the same protocol as ping. Perhaps there
had been some kind of mix-up? Could the EMS, by chance, have sent an
ISS alarm packet?

I woke the network team and got them to check the configuration. Aha!  
We were monitoring the address. It seems someone had mistyped
what should have been a 10.x.x.x address.

So our EMS was accidentally trying to manage the DIA's network
devices. But was it also the unwitting host of a hacked version of
Internet Scanner? We could find no evidence of any such tools on the
machine. It seemed much more likely that the "attack" was just an odd
packet. But with no record of the packet from our intrusion-detection
system, we faced a choice: We could either ask the DIA if they had a
copy, or we could keep our heads down.

We're keeping our heads down. I've updated the firewall to block any
attempts for the EMS to talk outward, and hopefully that's the end of
it. That is, unless the feds come knocking.

What do you think?

This week's journal is written by a real security manager, "Vince
Tuesday," whose name and employer have been disguised for obvious
reasons. Contact him at vince.tuesday@xxxxxxxxxxxx, or join the
discussion in our forum:


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