DOCUMENT:Q188348 TITLE :Specially-Malformed FTP Requests May Create Denial of Service PRODUCT :IIS PROD/VER:3.0 4.0 OPER/SYS:WINDOWS NT KEYWORD :prodiis4 prodiis3 ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Internet Information Server versions 3.0, 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== Specially-malformed FTP requests may create a Denial of Service in the FTP service, which causes Internet Information Server (IIS) to stop responding and generate an Access Violation error message. RESOLUTION ========== A supported fix that corrects this problem is now available from Microsoft, but has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next Windows NT service pack. To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web: http://support.microsoft.com/support/supportnet/default.asp The English version of this fix should have the following file attributes or later: Date Time Size File Name Platform ------------------------------------------------------------- 01/26/99 05:25p 27,696 Admwprox.dll (x86) 01/26/99 05:27p 327,472 Asp.dll (x86) 01/26/99 05:27p 33,872 Clusiis4.dll (x86) 01/26/99 05:28p 70,432 Convlog.exe (x86) 01/26/99 05:26p 81,376 Ftpsvc2.dll (x86) 01/26/99 04:39p 11,396 Httpext.h (x86) 01/26/99 05:26p 55,392 Httpodbc.dll (x86) 01/26/99 05:27p 65,664 Iisclex4.dll (x86) 01/26/99 05:25p 61,920 Iislog.dll (x86) 01/26/99 05:28p 786,432 Iis_u.dll (x86) 01/26/99 05:24p 24,288 Inetsloc.dll (x86) 01/26/99 05:25p 184,208 Infocomm.dll (x86) 01/26/99 05:24p 47,936 Isatq.dll (x86) 01/26/99 05:25p 29,520 Iscomlog.dll (x86) 01/26/99 05:26p 11,248 Iwrps.dll (x86) 01/26/99 05:26p 227,424 W3svc.dll (x86) 01/26/99 05:25p 87,504 Wam.dll (x86) 01/26/99 05:27p 49,424 Admwprox.dll (Alpha) 01/26/99 05:29p 548,112 Asp.dll (Alpha) 01/26/99 05:29p 53,520 Clusiis4.dll (Alpha) 01/26/99 05:30p 126,736 Convlog.exe (Alpha) 01/26/99 05:28p 126,224 Ftpsvc2.dll (Alpha) 01/26/99 04:43p 11,396 Httpext.h (Alpha) 01/26/99 05:28p 89,360 Httpodbc.dll (Alpha) 01/26/99 05:29p 114,960 Iisclex4.dll (Alpha) 01/26/99 05:27p 110,864 Iislog.dll (Alpha) 01/26/99 05:30p 956,176 Iis_u.dll (Alpha) 01/26/99 05:26p 43,792 Inetsloc.dll (Alpha) 01/26/99 05:27p 302,864 Infocomm.dll (Alpha) 01/26/99 05:26p 82,704 Isatq.dll (Alpha) 01/26/99 05:27p 45,840 Iscomlog.dll (Alpha) 01/26/99 05:28p 16,656 Iwrps.dll (Alpha) 01/26/99 05:28p 381,712 W3svc.dll (Alpha) 01/26/99 05:28p 149,264 Wam.dll (Alpha) IIS 4.0 The IIS 4.0 version of this hotfix must be installed over Windows NT 4.0 SP4. It has been posted to the following Internet location as Ftpls4i.exe (x86) and Ftpls4a.exe (Alpha): ftp://ftp.microsoft.com/bussys/iis/iis-public/fixes/usa/security/ftpls-fix/ IIS 3.0 The IIS 3.0 version of this hotfix must be installed over Windows NT 4.0 SP4. It has been posted to the following Internet location as Ftpls3i.exe (x86) and Ftpls3a.exe (Alpha): ftp://ftp.microsoft.com/bussys/iis/iis-public/fixes/usa/security/ftpls-fix/ NOTE: If you contact Microsoft to obtain this fix, a fee may be charged. This fee is refundable if it is determined that you only require the fix you requested. However, this fee is non-refundable if you request additional technical support, if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support. For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base: ARTICLE ID: Q154871 TITLE: Determining If Your Product Is Eligible for No-Charge Technical Support STATUS ====== Microsoft has confirmed this to be a problem in Internet Information Server versions 3.0 and 4.0. Additional query words: IIS hotfix hot fix qfe quick engineering patch ============================================================================ 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.