Vista’s Security Rendered Completely Useless by New Exploit

August 7, 2008 – 9:34 PM

This week at the Black Hat Security Conference two security researchers will discuss their findings which could completely bring Windows Vista to its knees.

Mark Dowd of IBM Internet Security Systems (ISS) and Alexander Sotirov, of VMware Inc. have discovered a technique that can be used to bypass all memory protection safeguards that Microsoft built into Windows Vista. These new methods have been used to get around Vista’s Address Space Layout Randomization (ASLR), Data Execution Prevention (DEP) and other protections by loading malicious content through an active web browser. The researchers were able to load whatever content they wanted into any location they wished on a user’s machine using a variety of scripting languages, such as Java, ActiveX and even .NET objects. This feat was achieved by taking advantage of the way that Internet Explorer (and other browsers) handle active scripting in the Operating System.

While this may seem like any standard security hole, other researchers say that the work is a major breakthrough and there is very little that Microsoft can do to fix the problems. These attacks work differently than other security exploits, as they aren’t based on any new Windows vulnerabilities, but instead take advantage of the way Microsoft chose to guard Vista’s fundamental architecture. According to Dino Dai Zovi, a popular security researcher, “the genius of this is that it’s completely reusable. They have attacks that let them load chosen content to a chosen location with chosen permissions. That’s completely game over.”

According to Microsoft, many of the defenses added to Windows Vista (and Windows Server 2008) were added to stop all host-based attacks. For example, ASLR is meant to stop attackers from predicting key memory addresses by randomly moving a process’ stack, heap and libraries. While this technique is very useful against memory corruption attacks, it would be rendered useless against Dowd and Sotirov’s new method. “This stuff just takes a knife to a large part of the security mesh Microsoft built into Vista,” said Dai Zovi. “If you think about the fact that .NET loads DLLs into the browser itself and then Microsoft assumes they’re safe because they’re .NET objects, you see that Microsoft didn’t think about the idea that these could be used as stepping stones for other attacks. This is a real tour de force.”

While Microsoft hasn’t officially responded to the findings, Mike Reavey, group manager of the Microsoft Security Response Center, said the company has been aware of the research and is very interested to see it once it has been made public. It currently isn’t known whether these exploits can be used against older Microsoft Operating Systems, such as Windows XP and Windows Server 2003, but since these techniques do not rely on any one specific vulnerability, Zovi believes that we may suddenly see many similar techniques applied to other platforms or environments. “This is not insanely technical. These two guys are capable of the really low-level technical attacks, but this is simple and reusable,” Dai Zovi said. “I definitely think this will get reused soon.”

These techniques are being seen as an advance that many in the security community say will have far-reaching implications not only for Microsoft, but also on how the entire technology industry thinks about attacks. Expect to be hearing more about this in the near future and possibly being faced with the prospect of your “secure” server being stripped completely naked of all its protection.


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