MS01-026: FTP Service Allows Login to Domain Guest Account

This article has been archived. It is offered "as is" and will no longer be updated.
Symptoms
In Microsoft Internet Information Services (IIS) 5.0 and Microsoft Internet Information Server (IIS) 4.0, if a user wants to log onto an FTP server by using a domain user account, rather than a local one, they are required to precede it with the name of the domain. However, if the user precedes an account name with a particular set of characters, a flaw causes the FTP service to search the domain and all trusted domains for the user account. If the user enters the correct password for the account, they are logged into it.

Mitigating Factors:
  • This vulnerability can only be exploited if the FTP server is a domain member. However, this is usually not appropriate for Internet-connected FTP servers.
  • This vulnerability can only be exploited if the Guest account on the local computer has been disabled, and the Guest account on a trusted domain is enabled. By default, the Guest account is disabled in Windows NT Server 4.0 and Windows 2000.
Cause
If a user ID is specified in a particular way when a user logs onto an affected FTP server, the system automatically searches all trusted domains for a user ID that matches it. If the user ID is found and the correct password is provided, the system will allow the user to log into it normally.
Resolution
For additional information on what is fixed by these patches, click the article number below to view the article in the Microsoft Knowledge Base:
297860 IIS 5.0 Security and Post-Windows NT 4.0 SP5 IIS 4.0 Patch Rollup

Internet Information Services 5.0

To resolve this problem, either obtain the hotfix referenced in this section or Windows 2000 Security Rollup Package 1 (SRP1). 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
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 theMicrosoft Knowledge Base:
260910 How to Obtain the Latest Windows 2000 Service Pack
The following file is 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   --------------------------------------------------------   05/04/2001  11:48a  5.0.2195.3554  245,520  Adsiis.dll   05/04/2001  11:48a  5.0.2195.3554  332,560  Asp.dll   08/26/2000  06:30p                   6,512  Fixerr.js   11/10/2000  11:21p  4.0.2.4701     593,976  Fp4autl.dll   03/27/2001  10:10p  0.9.3940.21    445,712  Httpext.dll   05/04/2001  11:48a  5.0.2195.3554   56,592  Httpodbc.dll   05/04/2001  11:48a  5.0.2195.3554  122,640  Iisrtl.dll   05/04/2001  11:48a  5.0.2195.3554   13,584  Infoadmn.dll   05/04/2001  11:48a  5.0.2195.3554  245,520  Infocomm.dll   05/04/2001  11:48a  5.0.2195.3554   62,736  Isatq.dll   05/04/2001  11:48a  5.0.2195.3554   46,352  Ism.dll   05/04/2001  11:48a  5.0.2195.3555   76,560  Msw3prt.dll   10/17/2000  01:38p  5.0.2195.2507    6,928  Schmupd.exe   05/04/2001  11:48a  5.0.2195.3554   41,232  Ssinc.dll   05/04/2001  11:48a  5.0.2195.3554    7,440  W3ctrs.dll   05/04/2001  11:48a  5.0.2195.3554  357,648  W3svc.dll				
NOTE: This patch can be installed on systems running Windows 2000 Gold, Windows 2000 Service Pack 1, or Windows 2000 Service Pack 2.

Internet Information Server 4.0

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that you determine are at risk of attack. Evaluate the computer's physical accessibility, network and Internet connectivity, and other factors to determine the degree of risk to the computer. See the associated Microsoft Security Bulletin to help determine the degree of risk. This hotfix may receive additional testing. If the computer is sufficiently at risk, we recommend that you apply this hotfix now.

To resolve this problem immediately, download the hotfix by following the instructions later in this article or contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site: Note In special cases, charges that are ordinarily incurred for support calls may be canceled, if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The following file is available for download from the Microsoft Download Center:
NOTE: Q295534is.exe contains the Symbols files.

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   --------------------------------------------------------   04/11/2001  01:32p  4.2.764.1      214,544  Adsiis.dll   04/11/2001  01:33p  4.2.764.1      330,672  Asp.dll   04/02/2001  04:55p  4.0.2.4701     593,976  Fp4autl.dll   04/11/2001  01:32p  4.2.764.1       81,888  Ftpsvc2.dll   04/11/2001  01:32p  4.2.764.1       55,392  Httpodbc.dll   04/11/2001  01:32p  4.2.764.1       98,912  Iischema.dll   04/11/2001  01:31p  4.2.764.1       63,472  Iislog.dll   04/11/2001  01:31p  4.2.764.1      185,792  Infocomm.dll   04/11/2001  01:31p  4.2.764.1       29,520  Iscomlog.dll   04/11/2001  01:35p  4.2.764.1       54,560  Ism.dll   04/02/2001  04:55p  4.0.1381.7086  375,056  Kernel32.dll   04/11/2001  01:36p  4.2.764.1        9,680  Schmupd.exe   04/11/2001  01:32p  4.2.764.1       38,256  Ssinc.dll   04/11/2001  01:32p  4.2.764.1       25,360  Sspifilt.dll   04/11/2001  01:32p  4.2.764.1      229,024  W3svc.dll   04/11/2001  01:31p  4.2.764.1       88,032  Wam.dll				
NOTE: This patch can be installed on systems running Windows NT 4.0 Service Pack 5 or Windows NT 4.0 Service Pack 6a.

Status
Microsoft has confirmed that this problem may cause a degree of security vulnerability in Internet Information Services 5.0 and Internet Information Server 4.0. 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, see the following Microsoft Web site:
kbIISCom security_patch kbWin2000srp1
Properties

Article ID: 288855 - Last Review: 06/19/2014 12:40:00 - Revision: 7.0

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