SYMPTOMS
A Simple Mail Transport Protocol (SMTP) service is installed by default in the Windows 2000 Server family of products. Exchange 2000, which you can install only on Windows 2000, uses the included Windows 2000 SMTP service instead of providing its own service. Windows 2000 Professional and Windows XP Professional include an SMTP service that is not installed by default. All of these implementations contain a flaw that could allow denial-of-service attacks to be mounted against the service.
The flaw involves the manner in which the service handles a particular type of SMTP command that is used to transfer the data that constitutes an incoming e-mail message. By sending a malformed version of this command, an attacker could stop the SMTP service or severely affect the performance of the SMTP service. This could disrupt mail services on the affected computer, but would not cause the operating system itself to stop working.
Mitigating Factors
- Microsoft Windows XP Home Edition does not include an SMTP service, and is not affected by the vulnerability.
- Windows 2000 Professional and Windows XP Professional do provide an SMTP service, but it is not installed by default.
- The Windows 2000 Server family of products install the SMTP service by default. However, best practices recommend that you disable any unnecessary services. Computers on which you have disabled the SMTP service are not at risk.
- Microsoft Exchange 5.5 is not affected by the vulnerability, even if it is installed on a Windows 2000-based server.
- The result of an attack would be limited to disrupting the SMTP service and, depending on the server's configuration, also possibly disrupting Microsoft Internet Information Services (IIS) and other Internet services. However, it would not disrupt any other server functions.
- The vulnerability would not enable an attacker to gain any privileges on the affected server, or to access users' e-mail or data.
RESOLUTION
Windows XP Professional
To resolve this problem, obtain the latest service pack for Windows XP. For additional information, click the following article number to view the article in the
Microsoft Knowledge Base:
322389 How to Obtain the Latest Windows XP Service Pack
The following file is available for download from the Microsoft Download Center:
Release Date: February 27, 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.
The English version of this fix should have the following file attributes or later:
Date Time Version Size File name
-----------------------------------------------------
06-Feb-2002 17:57 6.0.2600.28 431,104 Smtpsvc.dll
Windows 2000 and Exchange 2000
Because Exchange 2000 uses the Windows 2000 SMTP service, the Windows 2000 patch eliminates the vulnerability on all Windows 2000-based computers, including computers on which Exchange 2000 is installed.
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
The following file is available for download from the Microsoft Download Center:
Release Date: February 27, 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.
Note that this update also corrects the vulnerability that is described in the following Microsoft Knowledge Base article:
310669 MS02-011: An Authentication Flaw Could Allow Unauthorized Users to Be Authenticated on the SMTP Service
The English version of this fix should have the following file attributes or later:
Date Time Version Size File name
--------------------------------------------------------
05-Feb-2002 11:05 5.0.2195.4624 321,296 Aqueue.dll
05-Feb-2002 11:05 5.0.2195.4777 333,072 Asp.dll
05-Feb-2002 11:05 5.0.2195.3649 299,792 Fscfg.dll
05-Feb-2002 11:05 5.0.2195.4624 8,464 Ftpctrs2.dll
05-Feb-2002 11:05 5.0.2195.4624 6,416 Ftpmib.dll
05-Feb-2002 11:05 5.0.2195.4624 9,488 Httpmib.dll
05-Feb-2002 11:05 5.0.2195.4624 13,584 Infoadmn.dll
05-Feb-2002 11:05 5.0.2195.4624 246,032 Infocomm.dll
05-Feb-2002 11:05 5.0.2195.4624 62,736 Isatq.dll
05-Feb-2002 11:05 5.0.2195.4624 66,832 Mailmsg.dll
05-Feb-2002 11:05 5.0.2195.4624 38,160 Ntfsdrv.dll
04-Feb-2002 16:29 5.0.2195.4905 438,544 Smtpsvc.dll
05-Feb-2002 11:05 5.0.2195.4624 7,440 W3ctrs.dll
NOTE: Because of file dependencies, this update requires
Windows 2000 Service Pack 2.
