Summary

• A vulnerability in the Microsoft .NET Framework could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
  
  The vulnerability is due to improper parsing of crafted JavaScript Object Notation (JSON) data by the affected software. An unauthenticated, remote attacker could exploit this vulnerability by sending crafted JSON data with specific character sequences to a targeted system. If successful, the attacker could cause the system to crash or become unresponsive, resulting in a DoS condition.
  
  Microsoft has confirmed the vulnerability in a security bulletin and released software updates.

Indicators of Compromise

• Microsoft .NET Framework 2.0 SP2, 3.5, 3.5 SP1, 3.5.1, 4, and 4.5 are vulnerable when running on the following systems:

  • Windows XP SP3
  • Windows XP Professional x64 Edition SP2
  • Windows Server 2003 SP2
  • Windows Server 2003 x64 Edition and Itanium-based Systems SP2
  • Windows Vista SP2
  • Windows Vista x64 Edition SP2
  • Windows Server 2008 for 32-bit and x64-based Systems SP2
  • Windows Server 2008 for Itanium-based Systems SP2
  • Windows 7 for 32-bit and x64-based Systems SP1
  • Windows Server 2008 R2 for x64-based and Itanium-based Systems SP1
  • Windows 8 (32-bit and 64-bit) Systems
  • Windows Server 2012
  • Windows RT

Technical Information

• The vulnerability is due to improper parsing of crafted JSON data by the affected software.
  
  An unauthenticated, remote attacker could exploit this vulnerability by sending crafted JSON data with specific character sequences to a targeted system. If successful, the attacker could cause the system to crash or become unresponsive, resulting in a DoS condition.

Analysis

• To exploit the vulnerability, an attacker would need to send crafted JSON data to a targeted system. To achieve this objective, the attacker may require access to trusted, internal networks in which the targeted system may reside, which could limit the likelihood of a successful exploit.
  
  Microsoft has corrected this vulnerability by modifying the way the affected software handles JSON data encodings.
  
  The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the October 2013 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 October 2013

Safeguards

• Administrators are advised to apply the appropriate updates.
  
  Administrators are advised to allow only trusted users to have network access.
  
  Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
  
  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.

Vendor Announcements

• Microsoft has released a security bulletin at the following link: MS13-082

Fixed 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 Microsoft Update service. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.

Revision History

• Version	Description	Section	Date
  1	Initial Release		2013-October-08 18:11 GMT

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Affected Products

• The security vulnerability applies to the following combinations of products.
  
  

  Primary Products
  Microsoft, Inc.	.NET Framework	2.0 (SP2) | 3.5 (Base) | 3.5.1 (Base) | 4.0 (Base) | 4.5 (Base)

  Associated Products
  Microsoft, Inc.	Windows 7	for 32-bit systems (SP1) | for x64-based systems (SP1)
  	Windows 8	for 32-bit systems (Base) | for x64-based systems (Base)
  	Windows RT	Original Release (Base)
  	Windows Server 2003	Datacenter Edition (SP2) | Datacenter Edition, 64-bit (Itanium) (SP2) | Datacenter Edition x64 (AMD/EM64T) (SP2) | Enterprise Edition (SP2) | Enterprise Edition, 64-bit (Itanium) (SP2) | Enterprise Edition x64 (AMD/EM64T) (SP2) | Standard Edition (SP2) | Standard Edition, 64-bit (Itanium) (SP2) | Standard Edition x64 (AMD/EM64T) (SP2) | Web Edition (SP2)
  	Windows Server 2008	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 (SP1)
  	Windows Server 2012	Original Release (Base)
  	Windows Vista	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)