DOCUMENT:Q254142 30-APR-2002 [iis] TITLE :Sending a Large Escape Sequence Causes 100% CPU PRODUCT :Internet Information Server PROD/VER::4.0,5.0 OPER/SYS: KEYWORDS:kbSecurity kbWin2000PreSP1Fix kbWin2000sp1Fix kbgraphxlinkcritical ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Internet Information Server version 4.0 - Microsoft Internet Information Services version 5.0 ------------------------------------------------------------------------------- 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. RESOLUTION ========== Internet Information Services 5.0 (Windows 2000) ------------------------------------------------ To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, please see the following article in the Microsoft Knowledge Base: Q260910 How to Obtain the Latest Windows 2000 Service Pack The following files are available for download from the Microsoft Download Center: US English: DownloadDownload Q254142_w2k_sp1_x86_en.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20286) Arabic: DownloadDownload Q254142_w2k_sp1_x86_ar.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20342) Chinese (Simplified): DownloadDownload Q254142_w2k_sp1_x86_cn.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20343) Chinese (Traditional): DownloadDownload Q254142_w2k_sp1_x86_tw.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20349) German: DownloadDownload Q254142_w2k_sp1_x86_de.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20344) Hebrew: DownloadDownload Q254142_w2k_sp1_x86_he.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20345) Japanese: DownloadDownload Q254142_w2k_sp1_x86_ja.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20346) Korean: DownloadDownload Q254142_w2k_sp1_x86_ko.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20348) Release Date: For additional information about how to download Microsoft Support files, click the article number below to view the article in the Microsoft Knowledge Base: Q119591 How to Obtain Microsoft Support Files from Online Services Microsoft used the most current virus detection software available on the date of posting to scan this file for viruses. After it is posted, the file is housed on secure servers that 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: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20292) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20292) Chinese (Simplified): x86: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20312) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20312) Chinese (Traditional): x86: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20313) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20313) Dutch: x86: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20320) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20320) French: x86: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20319) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20319) German: x86: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20314) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20314) Japanese: x86: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20315) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20315) Korean: x86: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20316) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20316) Portuguese (Brazil): x86: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20317) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20317) Spanish: x86: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20318) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20318) Swedish: x86: DownloadDownload Escseq4i.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20321) Alpha: DownloadDownload Escseq4a.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=20321) For additional information about how to download Microsoft Support files, click the article number below to view the article in the Microsoft Knowledge Base: Q119591 How to Obtain Microsoft Support Files from Online Services Microsoft used the most current virus detection software available on the date of posting to scan this file for viruses. After it is posted, the file is housed on secure servers that 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: Q317636 Windows NT Server 4.0, Terminal Server Edition, Security Rollup Package STATUS ====== Windows 2000 ------------ Microsoft has confirmed this to be 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 this to be 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/security/bulletins/MS00-023.asp Additional query words: security_patch tsesrp ====================================================================== Keywords : kbSecurity kbWin2000PreSP1Fix kbWin2000sp1Fix kbgraphxlinkcritical Technology : kbiisSearch kbiis500 kbiis400 Version : :4.0,5.0 Hardware : ALPHA x86 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.