Microsoft .NET Framework contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on a targeted system. Updates are available.
Description
Microsoft .NET Framework contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on a targeted system.
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.
Warning Indicators
Microsoft .NET Framework versions 1.0 SP3, 1.1 SP1, 2.0 SP2, 3.0 SP2, 3.5 SP1, 3.5.1, and 4 are vulnerable when running on the following systems:
Windows XP Tablet Edition 2005 SP3 and prior
Windows XP Media Center Edition 2005 SP3 and prior
Windows XP SP3 and prior
Windows XP Professional x64 Edition SP2 and prior
Windows Server 2003 SP2 and prior
Windows Server 2003 x64 Edition SP2 and prior
Windows Server 2003 Itanium-based Edition SP2 and prior
Windows Vista SP2 and prior
Windows Vista x64 Edition SP2 and prior
Windows 7 for 32-bit Systems SP1 and prior
Windows 7 for x64-based Systems SP1 and prior
Windows Server 2008 for 32-bit Systems SP2 and prior
Windows Server 2008 for x64-based Systems SP2 and prior
Windows Server 2008 for Itanium-based Systems SP2 and prior
Windows Server 2008 R2 for x64-based Systems SP1 and prior
Windows Server 2008 R2 for Itanium-based Systems SP1 and prior
IntelliShield Analysis
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 serialization of objects.
The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the May 2012 security bulletin release. This Cisco bulletin, which assists administrators in identifying or mitigating these vulnerabilities using Cisco devices, is available at the following link: Cisco Applied Mitigation Bulletin: Microsoft Security Bulletin Release for May 2012
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS12-035
Impact
An unauthenticated, remote attacker could exploit this vulnerability to 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 over the system.
Technical Information
The vulnerability is due to improper handling of user-supplied data processed by the .NET Framework. The affected software improperly serializes untrusted input.
An unauthenticated, remote attacker could exploit the vulnerability by hosting an Extensible Application Markup Language (XAML) browser application (XBAP) and convincing a user to visit the malicious website. When the malicious XBAP is processed, untrusted data is treated as trusted, possibly leading to an error condition that the attacker could use to execute arbitrary code on the system with the privileges of the user or bypass CAS restrictions.
Safeguards
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.
Patches/Software
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 Windows Update website. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
Signatures
Cisco Systems Cisco Intrusion Prevention System (IPS) 6.0
Home Edition Base, SP1, SP2, SP3 | Media Center Edition 2005, Base | Original Release Base, SP1 | Professional Edition Base, SP1, SP2, SP3 | Professional Edition, 64-bit (Itanium) 2003 (itanium 2), Base, SP1, SP2 | Professional x64 (AMD/EM64T) Base, SP1, SP2 | Tablet PC Edition 2005, Base
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