Technical Information

Brief overview of the risk:
This security update resolves a vulnerability in Microsoft .NET Framework. The vulnerability could allow information disclosure if an attacker sends a specially crafted web request to an affected server that has custom error messages disabled. An attacker who successfully exploited the vulnerability would be able to view parts of a web configuration file, which could expose sensitive information.

Detailed Information on the risk:

An information disclosure vulnerability exists in ASP.NET that is caused when ASP.NET improperly handles certain requests on systems that have custom error messages disabled. An attacker who successfully exploited the vulnerability would be able to view parts of a web configuration file, which could expose sensitive information.
To exploit this vulnerability, an attacker could a send a specially crafted web request to an affected server with the intention of eliciting an error message that could disclose information pertaining to the source line that originated the exception. Ultimately, this could disclose information that was not intended to be accessible. The security update addresses the vulnerability by removing file content details from the error messages that were facilitating the information disclosure.

Further information on this exploit is available at : MS15-041

Windows Server 2003 Service Pack 2
Windows Server 2003 x64 Edition Service Pack 2
Windows Server 2003 with SP2 for Itanium-based Systems
Windows Vista Service Pack 2
Windows Vista x64 Edition Service Pack 2
Windows Server 2008 for 32-bit Systems Service Pack 2
Windows Server 2008 for x64-based Systems Service Pack 2
Windows Server 2008 for Itanium-based Systems Service Pack 2
Windows 7 for 32-bit Systems Service Pack 1
Windows 7 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1
Windows 8 for 32-bit Systems
Windows 8 for x64-based Systems
Windows 8.1 for 32-bit Systems
Windows 8.1 for x64-based Systems
Windows Server 2012 and Windows Server 2012 R2
Windows Server 2012 R2
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Windows Server 2012 (Server Core installation)
Windows Server 2012 R2 (Server Core installation)