By Joris Evers
Staff Writer, CNET News.com
August 4, 2006
LAS VEGAS -- While Microsoft talked up Windows Vista security at Black
Hat, a researcher in another room demonstrated how to hack the operating
Joanna Rutkowska, a Polish researcher at Singapore-based Coseinc, showed
that it is possible to bypass security measures in Vista that should
prevent unsigned code from running.
And in a second part of her talk, Rutkowska explained how it is possible
to use virtualization technology to make malicious code undetectable, in
the same way a rootkit does. She code-named this malicious software Blue
"Microsoft is investigating solutions for the final release of Windows
Vista to help protect against the attacks demonstrated," a representative
for the software maker said. "In addition, we are working with our
hardware partners to investigate ways to help prevent the virtualization
attack used by the Blue Pill."
At Black Hat, Microsoft gave out copies of an early Vista release for
attendees to test. The software maker is still soliciting feedback on the
successor to Windows XP, which is slated to be broadly available in
Rutkowska's presentation filled a large ballroom at Caesars Palace to
capacity, even though it was during the last time slot on the final day of
the annual Black Hat security confab here. She used an early test version
of Vista for her research work.
As one of the security measures in Vista, Microsoft is adding a mechanism
to block unsigned driver software to run on the 64-bit version of the
operating system. However, Rutkowska found a way to bypass the shield and
get her code to run. Malicious drivers could pose a serious threat because
they run at a low level in the operating system, security experts have
"The fact that this mechanism was bypassed does not mean that Vista is
completely insecure. It's just not as secure as advertised," Rutkowska
said. "It's very difficult to implement a 100 percent-efficient kernel
To stage the attack, however, Vista needs to be running in administrator
mode, Rutkowska acknowledged. That means her attack would be foiled by
Microsoft's User Account Control, a Vista feature that runs a PC with
fewer user privileges. UAC is a key Microsoft effort to prevent malicious
code from being able to do as much damage as on a PC running in
administrator mode, a typical setting on Windows XP.
"I just hit accept," Rutkowska replied to a question from the audience
about how she bypassed UAC. Because of the many security pop-ups in
Windows, many users will do the same without realizing what they are
allowing, she said.
Microsoft has touted Vista as its most secure version of Windows yet. It
is the first operating system client to go through the company's Security
Development Lifecycle, a process to vet code and stamp out flaws before a
"Windows Vista has many layers of defense, including the firewall, running
as a standard user, Internet Explorer Protected Mode, /NX support, and
ASLR, which help prevent arbitrary code from running with administrative
privileges," the Microsoft representative noted.
After the presentation on bypassing the driver shield, Rutkowska presented
a way to create the stealthy malicious software she code-named Blue Pill.
The technique uses Pacifica, a Secure Virtual Machine, from chipmaker
Advanced Micro Devices, to go undetected.
Blue Pill could serve as a backdoor for attackers, Rutkowska said. While
it was developed on Vista and AMD's technology, it should also work on
other operating systems and hardware platforms. "Some people suggested
that my work is sponsored by Intel, as I focused on AMD virtualization
technology only," she said, adding that is untrue.
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