Hacking IIS -- how sweet it is

[InfoSec News <isn () c4i org>]

http://www.theregister.co.uk/content/4/20960.html

By Thomas C Greene in Washington
Posted: 10/08/2001 at 19:29 GMT

We've looked over a few recent credit-card database compromises
brought to our attention by CardCops (formerly AdCops), an
organization which tries to get the straight dope on e-commerce hacks
directly from the blackhat community to better inform merchants of
threats to their systems.

The most recent victims CardCops has seen are on-line perfumery
StrawberryNet.com; computer retailer mWave.com; and a very large Texas
ISP called Stic.net, which gave up many thousands of credit card
details, along with the records of 500 businesses and their FTP
logins. All of the victims are running IIS 4 or 5 over Win-NT or 2K.

Not surprisingly, Microsoft IIS is quite popular among carders,
because its got lots and lots of holes, and because its often used by
people who lack the technical know-how to bung them. It's easy to use,
which makes it particularly attractive for those who want to break
into e-commerce on a shoestring, and particularly attractive as well
for those who just want to break in.

CardCops founder Dan Clements reckons that IIS is in use by roughly
fifty per cent of e-merchants, but represents over eighty per cent of
their data compromises.

Under its 'amnesty program,' CardCops seeks information from active
carders in exchange for a guarantee that they won't be tracked,
reported or otherwise harassed. The idea is to warn the merchants and
card issuers when they've been hacked, and to learn which exploits are
most popular and most successful.

One such submission posted recently caught our eye. It details the
sheer ease with which one can exploit the IIS folder traversal
vulnerability (which was also exploited by the sadmind/IIS worm for
the less-threatening business of defacing servers, as we reported
here).

Exploiting the folder traversal bug causes IIS to reveal any directory
on the logical drive that contains the Web directory and gives up
access to any file in it. It allows the user to escape from the Web
directory and access files elsewhere on the same drive. If the user
has his Web directories and system directories on the same drive,
bingo -- machine owned.

Mind you, MS issued a hotfix for this vulnerability in October of
2000, and the sadmind/IIS worm ought to have alerted quite a few
admins that they were open to it, but this seems not to have helped as
much as one would wish. Furthermore, the simple precaution of placing
Web directories and system directories on different drives would limit
the damage, but this also seems to be overlooked more often than not.

According to what we've seen -- a little how-to manual submitted to
CardCops -- finding a vulnerable IIS machine is pretty much like
shooting fish in a barrel.

The unique item here is the author's home-made progie, called
'Microsoft IIS Raper', which quickly scans chosen IP ranges,
automatically searching for vulnerable IIS machines.

The program also simplifies matters and speeds things up considerably
by trying to fetch cmd.exe directly via http. Whenever it hits, one
knows that the folder traversal vulnerability is working as it should.
After that, one simply installs a Trojan to keep the machine open in
case it should be patched later, and thus it's owned. (Savvy crackers
will patch the system fully at this point, to prevent competitors from
taking it over.)

Patch this

How can it be this easy to exploit a vulnerability that Microsoft
patched ten months ago, and which a recent worm highlighted to admins
with numerous page defacements?

"What's going on is that there are just too damn many patches. It's
simply impossible to keep up. I get weekly summaries of new
vulnerabilities and patches. One alert service listed 19 new patches
in a variety of products in the first week of March 2001. That was an
average week. Some of the listings affected my network, and many of
them did not. Microsoft Outlook had over a dozen security patches in
the year 2000. I don't know how the average user can possibly install
them all; he'd never get anything else done," Counterpane Internet
Security CTO Bruce Schneier remarks in a recent article.

It's a fair point indeed, though we have hopes that Microsoft will
soon make it a bit easier.

And as for the recent hacks, CardCops' Clements says that none of the
businesses or ISPs he's contacted recently, warning that they've been
hacked, have bothered to reply. However, Stic.net President David
Robertson told us that he was never contacted, and deems it "highly
unlikely" that his system had been compromised.

He's lately been "bouncing off the walls," he reports, trying to
contact AdCops for more information since press time.



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