Vulnerability in ASP.NET Could Allow Information Disclosure (2418042)

http://technet.microsoft.com/en-us/security/bulletin/MS10-070
updated to include applicability for .NET Framework 4 on Windows Server 2008 R2 for x64-based Systems

Microsoft Security Bulletin MS10-070 - Important

Vulnerability in ASP.NET Could Allow Information Disclosure (2418042)

Published: September 28, 2010 | Updated: October 26, 2011

Version: 4.2

General Information

Executive Summary

This security update resolves a publicly disclosed vulnerability in ASP.NET. The vulnerability could allow information disclosure. An attacker who successfully exploited this vulnerability could read data, such as the view state, which was encrypted by the server. This vulnerability can also be used for data tampering, which, if successfully exploited, could be used to decrypt and tamper with the data encrypted by the server. Microsoft .NET Framework versions prior to Microsoft .NET Framework 3.5 Service Pack 1 are not affected by the file content disclosure portion of this vulnerability.

This security update is rated Important for all supported editions of ASP.NET except Microsoft .NET Framework 1.0 Service Pack 3. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by additionally signing all data that is encrypted by ASP.NET. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

This security update also addresses the vulnerability first described in Microsoft Security Advisory 2416728.