MS01-026: Pattern-Matching Function Can Cause Access Violation on FTP Server
This article was previously published under Q293826
This article has been archived. It is offered "as is" and will no longer be updated.
A denial of service (DoS) vulnerability exists in Microsoft Internet Information Services (IIS) 5.0 and Microsoft Internet Information Server (IIS) 4.0 because the function that processes wildcard sequences in FTP commands does not always allocate sufficient memory when it performs pattern matching. Under unusual circumstances, it may be possible for an attacker to levy an FTP command containing a wildcard sequence that, when expanded, can overrun the allocated memory and cause an access violation.
This scenario can cause the IIS service (which provides both Web and FTP functionality) to fail. As a result, all Web or FTP sessions that are in progress at the time are severed, and no new sessions can be established until the IIS service is restarted. In IIS 5.0, the service restarts automatically. In IIS 4.0, operator intervention is required to restart the service.
The attacker cannot add, change, or delete data on the server through this vulnerability, nor can the attacker usurp any administrative privileges.
The attacker must be able to start an FTP session in order to exploit the vulnerability.
This problem occurs because of a flaw in a pattern-matching function that is used by at least one FTP command. Depending on the wildcard sequence that is entered and the specific configuration of the server's file system, it is possible for the resulting pattern to exceed the available memory and trigger an access violation. This, in turn, causes the IIS service to fail.
For additional information on what is fixed by the following 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 5.0To 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 PackThe English version of this fix should have the following file attributes or later:
Date Time Version Size File name -------------------------------------------------------- 5/31/2001 03:31p 5.0.2195.3649 245,520 Adsiis.dll 5/31/2001 03:31p 5.0.2195.3649 332,560 Asp.dll 5/29/2001 04:37p 188.8.131.5201 593,976 Fp4autl.dll 5/31/2001 03:31p 5.0.2195.3649 246,032 Httpext.dll 5/31/2001 03:31p 5.0.2195.3649 56,592 Httpodbc.dll 5/31/2001 03:31p 5.0.2195.3649 122,640 Iisrtl.dll 5/31/2001 03:31p 5.0.2195.3649 13,584 Infoadmn.dll 5/31/2001 03:31p 5.0.2195.3649 245,520 Infocomm.dll 5/31/2001 03:31p 5.0.2195.3649 62,736 Isatq.dll 5/31/2001 03:31p 5.0.2195.3649 46,352 Ism.dll 5/31/2001 03:31p 5.0.2195.3649 76,560 Msw3prt.dll 5/30/2001 03:40p 5.0.2195.3651 6928 Schmupd.exe 5/30/2001 03:40p 5.0.2195.3651 7952 Spiisupd.exe 5/31/2001 03:32p 5.0.2195.3649 41,232 Ssinc.dll 5/31/2001 03:32p 5.0.2195.3649 7440 W3ctrs.dll 5/31/2001 03:32p 5.0.2195.3649 353,040 W3svc.dll
Internet Information Server 4.0A 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:
Download Q295534i.exe nowFor additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:
NOTE: Q295534is.exe are the Symbols files.
NOTE: Q295534is.exe are the Symbols files.
119591 How to Obtain Microsoft Support Files from Online ServicesMicrosoft 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 184.108.40.20601 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.dllNOTE: You can install this patch on systems that are running Microsoft Windows NT 4.0 Service Pack 5 or Windows NT 4.0 Service Pack 6a.
Internet Information Services 5.0Microsoft has confirmed that this problem may cause a degree of security vulnerability in Internet Information Services 5.0. This problem was first corrected in Windows 2000 Service Pack 3.
Internet Information Server 4.0Microsoft has confirmed that this problem may cause a degree of security vulnerability in Internet Information Server 4.0.
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 ProductFor 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 RebootFor more information on this vulnerability, see the following Microsoft Web site:
Article ID: 293826 - Last Review: 11/02/2013 21:56:00 - Revision: 6.0
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