Microsoft Security Bulletin MS13-082 - Critical

• 10/11/2017
• 56 minutes to read
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Vulnerabilities in .NET Framework Could Allow Remote Code Execution (2878890)

Published: October 8, 2013 | Updated: April 7, 2016

Version: 1.2

General Information

Executive Summary

This security update resolves two privately reported vulnerabilities and one publicly disclosed vulnerability in Microsoft .NET Framework. The most severe of the vulnerabilities could allow remote code execution if a user visits a website containing a specially crafted OpenType font (OTF) file using a browser capable of instantiating XBAP applications.

This security update is rated Critical for Microsoft .NET Framework 3.0 Service Pack 2, Microsoft .NET Framework 3.5, Microsoft .NET Framework 3.5.1, Microsoft .NET Framework 4, and Microsoft .NET Framework 4.5 on affected editions of Microsoft Windows; it is rated Important for Microsoft .NET Framework 2.0 Service Pack 2 and Microsoft .NET Framework 3.5 Service Pack 1 on affected editions of Microsoft Windows.

The security update addresses the vulnerabilities by ensuring that the .NET Framework properly handles OpenType fonts, XML digital signatures, and document type definitions in JSON data encodings. For more information about the vulnerabilities, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

Recommendation. Most customers have automatic updating enabled and will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.

For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update immediately using update management software, or by checking for updates using the Microsoft Update service.

See also the section, Detection and Deployment Tools and Guidance, later in this bulletin.

Knowledge Base Article

• Knowledge Base Article: 2878890
• File Information: Yes
• SHA1/SHA2 hashes: Yes
• Known issues: None

Affected and Non-Affected Software

The following software has been tested to determine which versions or editions are affected. Other versions or editions are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, see Microsoft Support Lifecycle.

^[2]Windows RT security updates are provided via Windows Update.

Non-Affected Software

Non-Applicable Software

OpenType Font Parsing Vulnerability – CVE-2013-3128

A remote code execution vulnerability exists in the way that affected components handle specially crafted OpenType fonts (OTF). The vulnerability could allow remote code execution if a user visits a website hosting an XAML Browser Application (XBAP) containing a specially crafted OTF file. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2013-3128.

Mitigating Factors

Microsoft has not identified any mitigating factors for this vulnerability.

Workarounds

Microsoft has not identified any workarounds for this vulnerability.

FAQ

What is the scope of the vulnerability?
This is a remote code execution vulnerability.

What causes the vulnerability?
The vulnerability is caused when the .NET Framework attempts to parse a specially crafted OpenType font (OTF) embedded in an XAML Browser Application (XBAP).

What is the OpenType font format?
OpenType is a font format developed jointly by Microsoft and Adobe as an extension of Apple's TrueType font format. An OpenType font file contains data, in table format, that comprises either a TrueType or a PostScript outline font. Rasterizers use combinations of data from the tables contained in the font to render the TrueType or PostScript glyph outlines. For more information, see the Microsoft Typography OpenType FAQ.

What might an attacker use the vulnerability to do?
In a web-browsing scenario, an attacker who successfully exploited this vulnerability could execute arbitrary code on behalf of the targeted user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
In an attack scenario, an attacker could host an XAML Browser Application (XBAP) containing a specially crafted OTF file on a website. An attacker would have no way to force users to visit such a website. Instead, an attacker would have to convince users to visit the website, typically by getting them to click a link in an email message or in an Instant Messenger message that takes users to the attacker's website. It could also be possible for an attacker exploit this vulnerability by embedding specially crafted web content in banner advertisements or by using other methods to deliver web content to affected systems.

What is an XAML Browser Application (XBAP)?
An XAML browser application (XBAP) combines features of both a web application and a rich-client application. Like web applications, XBAPs can be published to a web server and launched from Internet Explorer. Like rich-client applications, XBAPs can take advantage of the capabilities of Windows Presentation Foundation (WPF). For more information about XBAPs, see MSDN article, Windows Presentation Foundation XAML Browser Applications Overview.

What systems are primarily at risk from the vulnerability?
Any systems running the affected versions of .NET Framework are affected by this vulnerability.

What systems are primarily at risk from the vulnerability?
In the web-browsing scenario, successful exploitation of this vulnerability requires that a user be logged on and visiting websites using a web browser capable of instantiating XBAP applications. Therefore, any systems where a web browser is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability. Servers could be at more risk if administrators allow users to browse and read email on servers. However, best practices strongly discourage allowing this.

What does the update do?
The update addresses the vulnerability by ensuring that the .NET Framework properly handles OpenType fonts.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.

Entity Expansion Vulnerability - CVE-2013-3860

A denial of service vulnerability exists in the .NET Framework that could allow an attacker to cause a server or application to crash or become unresponsive.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2013-3860.

Mitigating Factors

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

• Affected systems do not accept and validate XML digital signatures by default. An application on an affected system must be specifically coded to accept this type of data and subsequently validate its authenticity. Also, if the specially crafted XML data is not persistent, then application responsiveness is restored after a restart and will remain so unless the specially crafted data is reintroduced.

Workarounds

Microsoft has not identified any workarounds for this vulnerability.

FAQ

What is the scope of the vulnerability?
This is a denial of service vulnerability.

What causes the vulnerability?
The vulnerability is caused when the .NET Framework attempts to parse a specially crafted document type definition (DTD) for XML data when an XML digital signature is validated.

What is DTD?
DTD, standing for document type definition, is a file format type that is used in XML and other markup languages to identify the markup to be used to format a document.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited these cause an application or server to crash or become unresponsive until an administrator restarts the application or server.

How could an attacker exploit the vulnerability?
In an attack scenario, the attacker would send digitally signed XML data with a specially crafted DTD to an application that parses and validates XML data with digital signatures.

What systems are primarily at risk from the vulnerability?
Any systems running the affected versions of .NET Framework are affected by this vulnerability.

What does the update do?
The update addresses the vulnerability by ensuring that the .NET Framework properly validates XML digital signatures.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.

JSON Parsing Vulnerability - CVE-2013-3861

A denial of service vulnerability exists in the .NET Framework that could allow an attacker to cause a server or application to crash or become unresponsive.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2013-3861.

Mitigating Factors

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

• Only affected servers become unresponsive in an attack scenario; affected client systems are impacted in that their communication with an unresponsive server prevents them from rendering application content.
• Affected systems do not accept and validate JSON data by default. An application on an affected system must be specifically coded to accept this type of data and subsequently validate its authenticity. If the specially crafted JSON data is not persistent, then application responsiveness is restored after a restart. Only if an affected server accepts user input and sends it to a client system will the client system become unresponsive.

Workarounds

Microsoft has not identified any workarounds for this vulnerability.

FAQ

What is the scope of the vulnerability?
This is a denial of service vulnerability.

What causes the vulnerability?
The vulnerability is caused when the .NET Framework attempts to parse specially crafted JavaScript Object Notation (JSON) data.

What is JSON?
JSON, standing for JavaScript Object Notation, is an open standard format for human-readable data interchange. It is based on the JavaScript scripting language, but supports many languages and is mainly used to transmit data between servers and web applications.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could cause an application or server to crash or become unresponsive until an administrator restarts the application or server.

How could an attacker exploit the vulnerability?
In an attack scenario, an attacker would send JSON data with a specific character sequences to an application that parses JSON data.

What systems are primarily at risk from the vulnerability?
Any systems running the affected versions of .NET Framework are affected by this vulnerability.

What does the update do?
The update addresses the vulnerability by ensuring that the .NET Framework properly handles JSON data encodings.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
Yes. This vulnerability has been publicly disclosed.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.

Detection and Deployment Tools and Guidance

Several resources are available to help administrators deploy security updates.

• Microsoft Baseline Security Analyzer (MBSA) lets administrators scan local and remote systems for missing security updates and common security misconfigurations.
• Windows Server Update Services (WSUS), Systems Management Server (SMS), and System Center Configuration Manager help administrators distribute security updates.
• The Update Compatibility Evaluator components included with Application Compatibility Toolkit aid in streamlining the testing and validation of Windows updates against installed applications.

For information about these and other tools that are available, see Security Tools for IT Pros.

Security Update Deployment

Affected Software

For information about the specific security update for your affected software, click the appropriate link:

Windows XP (all editions)

Reference Table

The following table contains the security update information for this software.

Windows Server 2003 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows Vista (all editions)

Reference Table

The following table contains the security update information for this software.

Windows Server 2008 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows 7 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows Server 2008 R2 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows 8 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows Server 2012 (all editions)

Reference Table

The following table contains the security update information for this software.