Security Intelligence Operations

Microsoft Virtual PC and Virtual Server contain a vulnerability that could allow a local attacker to gain escalated privileges.

The vulnerability exists due to improper restrictions on some components within Virtual PC and Virtual Server. A local attacker with elevated access to the guest operating system could exploit this vulnerability by passing malicious input to affected components, corrupting memory within the host operating system. An attacker could take advantage of this memory corruption to execute arbitrary code with elevated privileges.

Microsoft has confirmed this vulnerability in a security bulletin and released software updates.

Systems running the following software are vulnerable:

• Microsoft Virtual PC 2004
• Microsoft Virtual Server 2005
• Microsoft Virtual Server 2005 R2
• Microsoft Virtual PC for Mac Version 6.1
• Microsoft Virtual PC for Mac Version 7

To exploit this vulnerability, an attacker must have administrative access to a virtual operating system that is hosted on an affected system. Such access may require that the attacker access a system locally, or via network access in some configurations. An exploit could allow the attacker to execute arbitrary code with elevated privileges, allowing the attacker to take complete control over the host or another guest operating system.

The update available from Microsoft corrects this vulnerability by adding controls to restrict access to affected components.

Microsoft has re-released a security bulletin at the following link: MS07-049