MS issues bum security patch, contradicts self

[InfoSec News <isn () c4i org>]

http://www.theregister.co.uk/content/4/22382.html

By Thomas C Greene in Washington
Posted: 22/10/2001 at 10:00 GMT

Recently-issued patches for an exploitable RDP (Remote Data Protocol)
bug in Win-NT and 2K have given users trouble enough for MS to yank
one of them (details below). The timing is unfortunate. Only last week
Microsoft Security Manager Scott Culp called on outside security
researchers to follow Redmond's no-tell bug reporting example
http://www.theregister.co.uk/content/55/22332.html.

One core issue is exploit code, and the examples are Nimda and Code
Red. "It's high time the security community stopped providing
blueprints for building these weapons," Culp said.

His aim is to keep exploitable data out of the hands of the Blackhat
development community, which, while perfectly legitimate, is a fairly
shaky proposition in practical terms. Blackhats are often well ahead
of vendors, as we've seen many times.

We certainly don't advocate broadcasting step-by-step exploit manuals
-- especially by the mainstream press and by security vendors which
stand to profit from abuse; but we believe that the tech press and
independent security lists should continue to publish detailed
information. We wish Microsoft would contribute the data they find, at
least after a patch has been issued.

We say this because system configurations vary and it's important to
verify that a given patch actually does the job in each case.
Withholding the information needed to prove that it works forces
admins to trust that it does. This can produce a false sense of
security, which is worse than incomplete security of which one is, at
least, aware.

For rigorous evaluation we need two things: a detailed description of
the bug, and as many working exploits as we can find to run against
the patch. Only then can we be confident that a patch is robust.

"Without exploit code, how do we ensure that the patches actually
work," VulnWatch http://www.vulnwatch.org moderator Steve Manzuik
asked in a recent letter to Culp.

"Trust our vendor? I don't think so. Vendors have proven that they bow
to stock prices and market pressures and will continue to do this over
and above security needs. Multiple vendors, not just Microsoft, have
also proved that they will not completely research the issues
themselves, and release insufficient patches," Manzuik says.

Funny that 

Talk about insufficient patches. MS concludes that the NT version of
their RDP-bug patch can be installed safely, while the 2K patch will
make a mess of your system and has been removed from the TechWeb site
pending a fix.

If you've downloaded the 2K patch and not yet installed it, then you
should discard it before some well-meaning OFH ninny goes ahead with
the installation for you.

The patch is not crucial as the RDP hole can't (yet) be exploited in a
destructive manner. A "particular series of data packets" will shut
the server down, but a simple re-boot is all that's needed to bring
things back. Of course, if one's being deliberately attacked with this
vulnerability, re-booting every fifteen minutes pretty much equals a
denial of service.

The systems affected are: NT Server 4.0, Terminal Server Edition; 2K
Server; 2K Advanced Server; and 2K Datacenter Server. The NT patch is
available here
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/
bulletin/ms01-052.asp; and the 2K patch will be posted as soon as
possible, MS says.

It would be nice if MS would specify the 'particular series of
packets' which triggers the RDP freeze, as it's quite possible there's
a simple workaround which might be applied as a stopgap. It would also
be nice to run an attack against one's own machine after patching, to
ensure that the fix is effective on one's system.

But that would require us to regard exploit code as a tool, not a
weapon. Unfortunately it's both, which is why it may never be possible
to reconcile these two quite legitimate, and eternally conflicting,
points of view. 



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