Vulnerability in ASP.NET Could Allow Information Disclosure (2418042)
Published: September 28, 2010
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.
Recommendation. Microsoft recommends that customers apply the update at the earliest opportunity.
From: The Microsoft Security Response Center (MSRC):
Date: Tuesday September 28, 2010
Time: 1:00 p.m. PDT
As we announced yesterday, today we released Security Bulletin MS10-070 out-of-band to address a vulnerability in ASP.NET. The bulletin and the blog by Scott Guthrie, corporate vice president of Microsoft's .NET Developer Platform are available for more information.
This security update addresses a vulnerability affecting all versions of the .NET Framework when used on Windows Server operating system. While desktop systems are listed as affected, consumers are not vulnerable unless they are running a web server from their computer.
The update will be made available initially only through the Microsoft Download Center and then released through Windows Update and Windows Server Update Services within the next few days. This allows customers the option to deploy it manually now without delaying for broader distribution.
For customers who use Automatic Updates, the update will be automatically applied once it is released broadly. Once the Security Update is applied, customers are protected against known attacks related to Security Advisory 2416728.