MS02-025: Malformed Mail Attribute Can Cause Exchange 2000 to Use Up CPU Resources (320436)


The information in this article applies to:

  • Microsoft Exchange 2000 Server
This article was previously published under Q320436

SYMPTOMS

A denial of service vulnerability exists in Microsoft Exchange 2000 Server. An attacker who can successfully make a direct connection to an Exchange 2000 Server and pass raw, hand-crafted mail messages directly to it can seek to exploit this vulnerability and cause the system to become unresponsive.

This vulnerability does not enable the attacker to gain any privileges on the system, nor to read, send, or delete any user's mail on the system. After the message had been processed, the system returns to normal.

CAUSE

This vulnerability results from a flaw in how Exchange 2000 Server handles mail messages with certain malformed message attributes. Instead of rejecting the malformed messages immediately, the Exchange 2000 Information Store service tries to process the message. In doing so, the Exchange 2000 Information Store service uses all available CPU and prevents any other services on the server from functioning during this period.

RESOLUTION

To resolve this problem, obtain the latest service pack for Microsoft Exchange 2000 Server. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

301378 XGEN: How to Obtain the Latest Exchange 2000 Server Service Pack

Download Information

The following files are available for download from the Microsoft Download Center:
English: DownloadDownload the Q320436 package now

French: DownloadDownload the Q320436 package now

German: DownloadDownload the Q320436 package now

Japanese: DownloadDownload the Q320436 package now

Release Date: May 29, 2002

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.

Installation Options

You do not have to restart your computer after you apply this update. However, you must use the /s option to install this hotfix. For additional information about the command options that you can use to apply this update, click the article number below to view the article in the Microsoft Knowledge Base:

257946 XGEN: GUI Hotfix Utility Switches /x /m /s /z

For example, the following command line installs the update without any user intervention, and does not force the computer to restart:

q320436enui386 /s

File Information

The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Component: Information Store 
   Date         Time   Version      Size       File name and Path
   ------------------------------------------------------------------------
   29-Apr-2002  15:04  6.0.5770.91    676,352  %EXSRVROOT%\Bin\Davex.dll
   29-Apr-2002  15:01  6.0.5770.91    578,116  %EXSRVROOT%\Bin\Dsaccess.dll
   29-Apr-2002  13:52  6.0.5770.91    180,736  %EXSRVROOT%\Bin\Dscmsg.dll
   29-Apr-2002  15:13  6.0.5770.91  3,518,976  %EXSRVROOT%\Bin\Excdo.dll
   29-Apr-2002  14:11  6.0.5770.91  1,860,096  %EXSRVROOT%\Bin\Exmgmt.exe
   29-Apr-2002  15:04  6.0.5770.91  1,683,968  %EXSRVROOT%\Bin\Exoledb.dll
   29-Apr-2002  15:04  6.0.5770.91    209,408  %EXSRVROOT%\Bin\Exprox.dll
   29-Apr-2002  13:41  6.0.5770.91    135,680  %CLUSTERDIR%\Exres.dll
   29-Apr-2002  13:51  6.0.5770.91    717,312  %EXSRVROOT%\Bin\Exsp.dll
   29-Apr-2002  14:11  6.0.5770.91  1,339,904  %EXSRVROOT%\Bin\Exwmi.dll
   29-Apr-2002  15:02  6.0.5770.91     41,532  %EXSRVROOT%\Bin\Jcb.dll
   29-Apr-2002  14:11  6.0.5770.91  2,949,632  %EXSRVROOT%\Bin\Mad.exe
   29-Apr-2002  14:10  6.0.5770.91  2,249,216  %EXSRVROOT%\RES\Mdbmsg.dll
   29-Apr-2002  14:17  6.0.5770.91    897,536  %EXSRVROOT%\Bin\Mdbsz.dll
   29-Apr-2002  14:59  6.0.5770.91    377,412  %EXSRVROOT%\Bin\Phatcat.dll
   29-Apr-2002  15:01  6.0.5770.91  4,547,136  %EXSRVROOT%\Bin\Store.exe
NOTE: If the cluster service is not detected during setup, the Exres.dll file is copied to the %EXSRVROOT%\Bin folder.

STATUS

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

MORE INFORMATION

For more information about this vulnerability, visit the following Microsoft Web site:

http://www.microsoft.com/technet/security/bulletin/MS02-025.mspx

Modification Type:MajorLast Reviewed:6/22/2004
Keywords:kbbug kbExchange2000preSP3fix kbExchange2000sp3fix kbfix KbSECHack kbSecurity KbSECVulnerability KB320436
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