Mark Dowd and Alexander Sotirov 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 objects, 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.

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.

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.