Microsoft Vulnerability Research Advisory MSVR12-014

Vulnerabilities in SumatraPDF Reader Could Allow Arbitrary Code Execution

Published: September 18, 2012

Version: 1.0

Overview

Executive Summary

Microsoft is providing notification of the discovery and remediation of multiple vulnerabilities affecting SumatraPDF Reader software version 2.0.1 and earlier. Microsoft discovered and disclosed the vulnerability under coordinated vulnerability disclosure to the affected vendor, SumatraPDF. SumatraPDF has remediated the vulnerabilities in their software.

Two vulnerabilities exist in the way that SumatraPDF Reader parses specially crafted PDF files. An attacker who successfully exploits either of these vulnerabilities could gain the same user rights as the current user. If the current user is logged on with administrative user rights, 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.

Microsoft Vulnerability Research reported this issue to and coordinated with SumatraPDF to ensure remediation of this issue. These vulnerabilities have been assigned the entries, CVE-2012-4895 and CVE-2012-4896, in the Common Vulnerabilities and Exposures list. For more information, including information about updates from SumatraPDF, see the release notes for the project.

Mitigating Factors

  • These vulnerabilities cannot be exploited automatically through email. For an attack to be successful, a user must open an attachment that is sent in an email message.
  • In a web-based attack scenario, an attacker could host a website that contains a specially crafted file that is used to exploit these vulnerabilities. In addition, compromised websites and websites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit the vulnerabilities. In all cases, however, an attacker would have no way to force users to visit these websites. 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 Instant Messenger message that takes users to the attacker’s website, and then convince them to open the specially crafted file.
  • An attacker who successfully exploited either of these vulnerabilities could gain the same user rights as the current user. 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.

Advisory Details

Purpose and Recommendation

Purpose of Advisory: To notify users of vulnerabilities and their remediation.

Advisory Status: Advisory published.

Recommendation: Review the Suggested Actions section and configure as appropriate.

Issue References

For more information about this issue, see the following references:

Reference Identification
Common Vulnerabilities and Exposures CVE-2012-4895 \ CVE-2012-4896

Affected and Non-Affected Software

This advisory discusses the following software:

Affected Software
SumatraPDF Reader version 2.0.1 and earlier
Non-Affected Software
SumatraPDF Reader version 2.1

Frequently Asked Questions

What is the scope of this advisory?
This advisory is part of a coordinated release with affected vendors to inform customers of a security issue that may affect their systems.

Are these security vulnerabilitiesthat require Microsoft to issue a security update?
No. The vulnerabilities have been fixed via an update from the affected third-party vendors. The update remediates the software listed in the table, Affected Software.

What is the scope of the vulnerabilities?
These are remote code execution vulnerabilities.

What causes the vulnerabilities?
These vulnerabilities are caused when SumatraPDF Reader improperly handles memory while parsing specially crafted PDF files.

What might an attacker use these vulnerabilities to do?
An attacker who successfully exploited either of these vulnerabilities could run arbitrary code in the security context of the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited either of these vulnerabilities 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. 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 vulnerabilities?
An attacker could exploit these vulnerabilities by tricking a user into opening a specially crafted file with an affected version of SumatraPDF Reader. Typically specially crafted files are delivered via social engineering techniques in email, instant messaging, or via download links on websites. These vulnerabilities cannot be exploited without user interaction.

Suggested Actions

Upgrade to the latest version of SumatraPDF Reader.

Other Information

Acknowledgments

Microsoft thanks the following:

  • John Leitch of Microsoft and SumatraPDF for working toward a resolution

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Revisions

  • V1.0 (September 18, 2012): Advisory published.

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