Knowledge Base

MS01-013: Windows 2000 Event Viewer Contains an Unchecked Buffer

Article ID: 285156

Article Last Modified on 1/29/2007

APPLIES TO

Microsoft Windows 2000 Service Pack 1
Microsoft Windows 2000 Service Pack 2
Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Service Pack 1
Microsoft Windows 2000 Service Pack 2

This article was previously published under Q285156

SYMPTOMS

The Windows 2000 Event Viewer snap-in has an unchecked buffer in a section of the code that displays the detailed view of event records. If Event Viewer attempts to display an event record that contains specially malformed data in one of the fields, either of two outcomes can occur. In the less serious case, Event Viewer could stop working. In the more serious case, code of a malicious user's choice could be made to run by using a buffer overrun.

By design, unprivileged processes can log events in the System and Application logs, and interactively logged-on, unprivileged users can view them. However, only privileged processes can log events in the Security log, and only interactively logged-on administrators can view them. If the vulnerability were exploited to run code of a malicious user's choice, the code would run in the security context of the user who viewed the affected record.

Mitigating Factors

Simply perusing the listing of events in a log would not allow the vulnerability to be exploited. It could only be exploited if the user opened an affected record to view the event details.
Although Event Viewer might be considered to be an administrative tool, there is no guarantee that the user who opens a particular event record would be privileged. Unprivileged users can read the System and Application logs. Although the Security log can be read only by privileged users, only privileged processes can write to it.
Microsoft believes that it is not possible to manipulate the typical auditing functions of any Windows 2000 service to create an event record that would exploit this vulnerability. Instead, custom code would need to be created and run to create such a record.
If you are using a firewall and are taking other appropriate precautions, only authenticated users have access to network computers and can write event log records.

RESOLUTION

To resolve this problem, either obtain Windows 2000 Service Pack 3 or Windows 2000 Security Rollup Package 1 (SRP1). To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910 How to Obtain the Latest Windows 2000 Service Pack

For additional information about SRP1, click the article number below to view the article in the Microsoft Knowledge Base:

311401 Windows 2000 Security Rollup Package 1 (SRP1), January 2002

The following files are available for download from the Microsoft Download Center:

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file. The English version of this fix should have the following file attributes or later:

   Date         Time   Version             Size   File name
   --------------------------------------------------------
   30-Jul-2001  14:57  5.0.2195.3649     157,456  Els.dll

STATUS

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Microsoft Windows 2000. This problem was first corrected in Windows 2000 Service Pack 3.

MORE INFORMATION

For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:

265173 The Datacenter Program and Windows 2000 Datacenter Server Product

For additional information about how to install multiple hotfixes with only one reboot, click the article number below to view the article in the Microsoft Knowledge Base:

296861 Use QChain.exe to Install Multiple Hotfixes with One Reboot

For more information on this vulnerability, please see the following Microsoft Web site:

http://www.microsoft.com/technet/security/bulletin/ms01-013.mspx

Additional query words: security_patch kbWin2000srp1 Patch Available for Malformed Event Record Vulnerability

Keywords: kbbug kbfix kbwin2000presp3fix kbgraphxlinkcritical kbsecvulnerability kbqfe kbwin2000sp3fix kbsecurity kbsecbulletin kbhotfixserver KB285156

Microsoft KB Archive/285156

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