Microsoft .NET Framework contains a vulnerability that could allow an unauthenticated, remote attacker to bypass security restrictions and execute arbitrary code on a targeted system. Updates are available.
Microsoft .NET Framework contains a vulnerability that could allow an unauthenticated, remote attacker to bypass security restrictions and execute arbitrary code.
The vulnerability is due to improper handling of user-supplied data processed by the .NET Framework. An unauthenticated, remote attacker could exploit the vulnerability by convincing a user to visit a malicious website. If successful, the attacker could execute arbitrary code on the system with the privileges of the user or bypass Code Access Security (CAS) restrictions.
Microsoft confirmed the vulnerability in a security bulletin and released software updates.
The following Microsoft products are affected:
Microsoft .NET Framework version 4 when installed on the following:
Windows XP SP3, Professional x64 Edition SP2
Windows Server 2003 SP2, x64 Edition SP2 and for Itanium-based Systems SP2
Windows Vista SP2 and x64 Edition SP2
Windows Server 2008 (32-bit, x64 and Itanium) SP2
Windows 7 for (32-bit and x64) SP1 and prior
Windows Server 2008 R2 (x64 and Itanium) SP1 and prior
Microsoft .NET Framework 4.5 when installed on the following:
Windows Vista SP2 and x64 Edition SP2
Windows Server 2008 for x64-based Systems SP2
Windows 7 for (32-bit and x64) SP1
Windows Server 2008 R2 for x64-based Systems SP1
Windows 8 (32-bit and x64)
Windows Server 2012
To exploit the vulnerability, the attacker may provide a link that directs a user to a malicious site and use misleading language or instructions to persuade the user to follow the provided link.
Microsoft has corrected this vulnerability by modifying the way the Microsoft .NET Framework handles the validation of objects performing reflections.
Microsoft has released a security bulletin at the following link: MS12-074
An unauthenticated, remote attacker could exploit this vulnerability to bypass security restrictions and execute arbitrary code on a targeted system with the privileges of the targeted user. If the user holds elevated privileges, the attacker could gain complete control of the system.
The vulnerability is due to improper handling of user-supplied data processed by the .NET Framework. The affected software performs insufficient validation of permissions on objects performing Windows Presentation Foundation (WPF) reflection optimization.
An unauthenticated, remote attacker could exploit the vulnerability by hosting an Extensible Application Markup Language (XAML) browser application (XBAP) and persuading a user to visit the malicious website. When the malicious XBAP is processed, untrusted data is treated as trusted, which could lead to an error condition that could allow an attacker to bypass security restrictions and execute arbitrary code on the system with the privileges of the user or bypass CAS restrictions. If the user holds elevated privileges, the attacker could gain complete control of the system.
Administrators are advised to apply the appropriate updates.
Users are advised not to open e-mail messages from suspicious or
unrecognized sources. If users cannot verify that links or attachments
included in e-mail messages are safe, they are advised not to open them.
Administrators may consider disabling XAML browser applications in Internet Explorer.
Administrators may consider adding trusted sites to the Internet Explorer Trusted sites zone.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
Administrators are advised to monitor affected systems.
Microsoft customers can obtain updates directly by using the links in the security bulletin. These updates are also distributed by Windows automatic update features and available on the Microsoft Update service. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
Datacenter Edition SP2 | Datacenter Edition, 64-bit SP2 | Itanium-Based Systems Edition SP2 | Enterprise Edition SP2 | Enterprise Edition, 64-bit SP2 | Essential Business Server Standard SP2 | Essential Business Server Premium SP2 | Essential Business Server Premium, 64-bit SP2 | Standard Edition SP2 | Standard Edition, 64-bit SP2 | Web Server SP2 | Web Server, 64-bit SP2
Windows Server 2008 R2
x64-Based Systems Edition SP1 | Itanium-Based Systems Edition Base, SP1
Windows Server 2012
Original Release Base
Home Basic SP2 | Home Premium SP2 | Business SP2 | Enterprise SP2 | Ultimate SP2 | Home Basic x64 Edition SP2 | Home Premium x64 Edition SP2 | Business x64 Edition SP2 | Enterprise x64 Edition SP2 | Ultimate x64 Edition SP2
Professional Edition SP3 | Professional x64 (AMD/EM64T) SP2
for 32-bit systems Base | for x64-based systems Base
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