Microsoft KB Archive/254142

= MS00-023: 100% CPU Usage Occurs When You Send a Large Escape Sequence =

Article ID: 254142

Article Last Modified on 11/21/2006

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APPLIES TO


 * Microsoft Internet Information Server 4.0
 * Microsoft Internet Information Services 5.0

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This article was previously published under Q254142



SYMPTOMS
When you send a large escape sequence to a computer running Internet Information Server 4.0 or Internet Information Services 5.0, the computer may use 100 percent CPU while it is processing the request. During this time, the server may not respond to other requests.



CAUSE
This problem occurs because the Str::unescape function parses the escape characters in the request string by processing one character at a time, shifting the data over each time, and then starting again from the beginning of the request string. This takes a considerable amount of CPU usage, and can cause the server to stop processing other requests.



Internet Information Services 5.0 (Windows 2000)
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 files are available for download from the Microsoft Download Center:

US English:

Download Q254142_w2k_sp1_x86_en.exe now

Arabic:

Download Q254142_w2k_sp1_x86_ar.exe now

Chinese (Simplified):

Download Q254142_w2k_sp1_x86_cn.exe now

Chinese (Traditional):

Download Q254142_w2k_sp1_x86_tw.exe now

German:

Download Q254142_w2k_sp1_x86_de.exe now

Hebrew:

Download Q254142_w2k_sp1_x86_he.exe now

Japanese:

Download Q254142_w2k_sp1_x86_ja.exe now

Korean:

Download Q254142_w2k_sp1_x86_ko.exe now

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.

Internet Information Server 4.0
The following files are available for download from the Microsoft Download Center:

US English:

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

Chinese (Simplified):

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

Chinese (Traditional):

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

Dutch:

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

French:

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

German:

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

Japanese:

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

Korean:

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

Portuguese (Brazil):

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

Spanish:

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

Swedish:

x86: Download Escseq4i.exe now

Alpha: Download Escseq4a.exe now

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    Platform -  2-24-2000 8:15:06pm  4.2.740.1     185,760b Infocomm.dll x86 2-24-2000 8:16:02pm 4.2.740.1     38,256b  Ssinc.dll    x86 2-24-2000 8:16:10pm 4.2.740.1     25,360b  Sspifilt.dll x86 2-24-2000 8:15:50pm 4.2.740.1     228,480b W3svc.dll    x86

2-25-2000 12:15:19am 4.2.740.1    304,400b Infocomm.dll alpha 2-25-2000 12:16:14am 4.2.740.1    60,176b  Ssinc.dll    alpha 2-25-2000 12:16:20am 4.2.740.1    39,696b  Sspifilt.dll alpha 2-25-2000 12:16:01am 4.2.740.1    383,760b W3svc.dll    alpha

Microsoft Windows NT Server version 4.0, Terminal Server Edition
To resolve this problem, obtain the Windows NT Server 4.0, Terminal Server Edition, Security Rollup Package (SRP). For additional information about the SRP, click the article number below to view the article in the Microsoft Knowledge Base:

317636 Windows NT Server 4.0, Terminal Server Edition, Security Rollup Package



Windows 2000
Microsoft has confirmed that this is a problem in Internet Information Services 5.0. This problem was first corrected in Windows 2000 Service Pack 1.

Windows NT 4.0
Microsoft has confirmed that this is a problem in Internet Information Server 4.0.



MORE INFORMATION
When you install this fix, the Str::unescape function traverses the request string only one time.

For additional information, please see the Microsoft Security Bulletin at the following Microsoft Web site:

http://www.microsoft.com/technet/security/Bulletin/MS00-023.mspx

Additional query words: security_patch tsesrp

Keywords: kbbug kbfix kbwin2000sp1fix kbgraphxlinkcritical kbqfe kbsecurity kbhotfixserver KB254142

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