Microsoft Security Bulletin MS07-037 - Important Vulnerability in Microsoft Office Publisher 2007 Could Allow Remote Code Execution (936548)

Microsoft Security Bulletin MS07-037 - Important
Vulnerability in Microsoft Office Publisher 2007 Could Allow Remote Code Execution (936548)
Published: July 10, 2007

Version: 1.0
General Information
Executive Summary

This important security update resolves one publicly disclosed vulnerability. This vulnerability could allow remote code execution if a user viewed a specially crafted Microsoft Office Publisher file. 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. User interaction is required to exploit this vulnerability.

This is an important security update for supported releases of Microsoft Office Publisher 2007. For more information, see the subsection, Affected and Non-Affected Software, in this section.

This security update addresses the vulnerability by modifying the way that Microsoft Office Publisher 2007 handles malformed .pub files. 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. Microsoft recommends that customers should apply the update at the earliest opportunity.

Known Issues. None
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Affected and Non-Affected Software

The software listed here 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, visit Microsoft Support Lifecycle.

Affected Software
Office Suite and Other Affected Software Component Maximum Security Impact Aggregate Severity Rating Bulletins Replaced by This Update

2007 Microsoft Office System

Microsoft Office Publisher 2007

Remote Code Execution

Important

None

Non-Affected Software
Office Suite Application

Microsoft Office 2000 Service Pack 3

Microsoft Publisher 2000

Microsoft Office XP Service Pack 3

Microsoft Publisher 2002

Microsoft Office 2003 Service Pack 2

Microsoft Publisher 2003
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Frequently Asked Questions (FAQ) Related to This Security Update

I am using an older release of the software discussed in this security bulletin. What should I do?
The affected software listed in this bulletin have been tested to determine which releases are affected. Other releases are past their support life cycle. To determine the support life cycle for your software release, visit Microsoft Support Lifecycle.

It should be a priority for customers who have older releases of the software to migrate to supported releases to prevent potential exposure to vulnerabilities. For more information about the Windows Product Lifecycle, visit the following Microsoft Support Lifecycle. For more information about the extended security update support period for these software releases, visit the Microsoft Product Support Services Web site.

Customers who require custom support for older software must contact their Microsoft account team representative, their Technical Account Manager, or the appropriate Microsoft partner representative for custom support options. Customers without an Alliance, Premier, or Authorized Contract can contact their local Microsoft sales office. For contact information, visit the Microsoft Worldwide Information Web site, select the country, and then click Go to see a list of telephone numbers. When you call, ask to speak with the local Premier Support sales manager. For more information, see the Windows Operating System Product Support Lifecycle FAQ.
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Vulnerability Information

Severity Ratings and Vulnerability Identifiers
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Publisher Invalid Memory Reference Vulnerability – CVE-2007-1754 Aggregate Severity Rating

Microsoft Office Publisher 2007

Important

Remote Code Execution

Important
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Publisher Invalid Memory Reference Vulnerability – CVE-2007-1754

A remote code execution vulnerability exists in the way Publisher does not adequately clear out memory resources when writing application data from disk to memory. An attacker could exploit the vulnerability by constructing a specially crafted Publisher (.pub) page. When a user views the .pub page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could take complete control of an affected system.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2007-1754.

Mitigating Factors for Publisher Invalid Memory Reference Vulnerability – CVE-2007-1754

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:
•

An attacker who successfully exploited this vulnerability could gain the same user rights as the local 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.
•

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability In addition, Web sites that accept or host user-provided content, or compromised Web sites and advertisement servers could contain specially crafted content that could exploit this vulnerability. Instead, an attacker would have to persuade users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users to the attacker's Web site.
•

2007 Microsoft Office System will show a prompt with Open, Save, or Cancel before opening a document from the Internet or restricted sites zone.
•

The vulnerability cannot be exploited automatically through e-mail. For an attack to be successful a user must open an attachment that is sent in an e-mail message.
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Workarounds for Publisher Invalid Memory Reference Vulnerability – CVE-2007-1754

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:
•

Do not open or save Microsoft Office files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
•

Modify Access Control List on pubconv.dll

To modify the Access Control List (ACL) on pubconv.dll to be more restrictive, follow these steps:

Click Start, click Run, type "cmd" (without the quotation marks), and then click OK.

Type the following command at a command prompt. Make a note of the current ACLs that are on the file (including inheritance settings) for future reference in case you have to undo this modification:

cacls \Program Files\Microsoft Office\Office12\pubconv.dll

Type the following command at a command prompt to deny the ‘everyone’ group access to this file:

cacls \Program Files\Microsoft Office\Office12 /d everyone

Impact of Workaround: Applications that require the use of previous editions of Publisher documents may no longer function correctly.
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FAQ for Publisher Invalid Memory Reference Vulnerability – CVE-2007-1754

What is the scope of the vulnerability?
If successfully exploited, this remote code execution vulnerability could allow the attacker to run arbitrary code as the logged-on user.

What causes the vulnerability?
Publisher does not correctly validate memory values read from a malformed file.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could make changes to the system with the permissions of the logged-on user. If a user is logged in 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?
This vulnerability requires that a user open a specially crafted Publisher file with an affected version of Microsoft Office Publisher.

In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially-crafted file to the user and by convincing the user to open the file.

In a Web-based attack scenario, an attacker would have to host a Web site that contains a Publisher file that is used to attempt to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content could contain specially crafted content that could exploit this vulnerability. An attacker would have no way to force users to visit a specially crafted Web site. Instead, an attacker would have to persuade them to visit the Web site, typically by getting them to click a link that takes them to the attacker's site.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Publisher is used are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.

What does the update do?
The update removes the vulnerability by correctly validating memory values read from a file.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

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 and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
Acknowledgments

Microsoft thanks the following for working with us to help protect customers:

eEye for reporting the Publisher Invalid Memory Reference Vulnerability - CVE-2007-1754.
Disclaimer

The information provided in the Microsoft Knowledge Base 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.
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Revisions
•

V1.0 (July 10, 2007): Bulletin published.