DOCUMENT:Q246401 16-MAY-2002 [iis] TITLE :MS99-061: IIS May Improperly Parse Specific Escape Characters PRODUCT :Internet Information Server PROD/VER::3.0,4.0,4.0 SP3,4.0 SP4,4.0 SP5,4.0 SP6 OPER/SYS: KEYWORDS:kbSecurity kbOSWinNT400sp4 kbiis400 kbOSWinNT400sp6 kbWinNT400PreSP7Fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Internet Information Server version 4.0 - Microsoft Site Server version 3.0 - Microsoft Windows NT Server versions 4.0 SP3, 4.0 SP4, 4.0 SP5, 4.0 SP6 ------------------------------------------------------------------------------- SYMPTOMS ======== RFC 1738 specifies that Web Servers should allow hexadecimal digits to be input in URLs by preceding them with the so-called "escape" character, a percent sign. Microsoft Internet Information Server (IIS) complies with the RFC 1738 specification, but also accepts characters after the percent sign that are not hexadecimal digits. Some of these translate to printable ASCII characters, and this could provide an alternate means of specifying files in URLs. It is possible when using the Internet Database Connector (IDC) to create links, or you are using the return value arguments passed to other documents. When this happens you may be unable to pass arguments that contain spaces. IIS 4.0 may improperly translate non-hexadecimal characters preceded by a percent sign. For example %3p is translated into an \\\"I\\\". The vulnerability does not affect IIS; even specifying a file name through this alternate method does not bypass IIS access controls. However, third-party software that runs atop IIS but does not perform canonicalization, is affected by it. RESOLUTION ========== Windows NT 4.0 -------------- The following files are available for download from the Microsoft Download Center: US English: x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16357) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16358) Dutch: x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=18985) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=18984) French: x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=18983) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=18982) German: x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16359) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16360) Japanese: x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16361) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16362) Korean: x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16363) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16364) Portuguese (Brazilian) x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=18979) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=18978) Simplified Chinese: x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16351) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16354) Spanish: x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=18981) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=18980) Traditional Chinese: x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16355) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=16356) Swedish: x86: DownloadDownload Unschx4i.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=18987) Alpha: DownloadDownload Unschx4a.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=18986) 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. 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 ====== Microsoft has confirmed this to be a problem in Internet Information Server 4.0. MORE INFORMATION ================ For related information about this problem, please visit the following Microsoft Web site: http://www.microsoft.com/security/bulletins/MS99-061.asp For additional security-related information about Microsoft products, please visit the following Microsoft Web site: http://www.microsoft.com/security/ Additional query words: iisscript asp iiswww iisvirtual security_patch tsesrp ====================================================================== Keywords : kbSecurity kbOSWinNT400sp4 kbiis400 kbOSWinNT400sp6 kbWinNT400PreSP7Fix Technology : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTS400sp6 kbWinNTS400sp5 kbWinNTS400sp4 kbWinNTS400sp3 kbWinNTS400search kbSiteServSearch kbiisSearch kbAudDeveloper kbiis400 kbSiteServ300 Version : :3.0,4.0,4.0 SP3,4.0 SP4,4.0 SP5,4.0 SP6 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.