DOCUMENT:Q287537 18-MAY-2001 [iis] TITLE :Using Basic Authentication to Generate Kerberos Tokens PRODUCT :Internet Information Server PROD/VER::5.0 OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Internet Information Services version 5.0 ------------------------------------------------------------------------------- SUMMARY ======= When you use Basic authentication to connect to a Web site that is hosted by Internet Information Services (IIS), you can take advantage of the delegation features of Kerberos to authenticate on multiple back-end servers, such as a Microsoft SQL Server that is called from Active Server Pages (ASP) running on IIS. To generate a Kerberos token, IIS must be a member of a Windows 2000 domain and have access to that domain's active directory. MORE INFORMATION ================ When IIS authenticates users it does so by calling the LsaLogonUser function, which in turn calls an authentication package (MICROSOFT_AUTHENTICATION_PACKAGE_V1_0 for Basic authentication). When Basic authentication occurs, the following event is written to the security log IIS 5.0 server, assuming the Audit Logon Events policy is enabled: Event Type: Success Audit Event Source: Security Event Category: Logon/Logoff Event ID: 528 Date: 1/5/2001 Time: 6:11:04 PM User: Win2kDomain\rvittal Computer: IIS5server Description: Successful Logon: User Name: rvittal Domain: Win2kDomain Logon ID: (0x0,0x148D0AC) Logon Type: 2 Logon Process: IIS Authentication Package: MICROSOFT_AUTHENTICATION_PACKAGE_V1_0 Workstation Name: IIS5server
After a user has logged into IIS with Basic authentication, IIS has that user's credentials (username:password), and can use those credentials to generate a token that can be used to impersonate the user on other computers. When a user requests a Web page that references resources on another Windows 2000 server, the IIS server generates a Kerberos security token and an event similar to the following is written in the security log on the remote server: Event Type: Success Audit Event Source: Security Event Category: Logon/Logoff Event ID: 540 Date: 1/5/2001 Time: 1:16:06 PM User: Win2kDomain\rvittal Computer: SQLbox Description: Successful Network Logon: User Name: rvittal Domain: Win2kDomain Logon ID: (0x0,0x13A667F) Logon Type: 3 Logon Process: Kerberos Authentication Package: Kerberos Workstation Name: Note that using Kerberos is not limited to Basic authentication. By default, if a Windows 2000 client attaches to an IIS5 server that is configured with Integrated authentication, Kerberos authentication is used. REFERENCES ========== This article is based on the information provided on page 109 of the following book: Howard, Michael, Richard Waymire, and Marc Levy. Designing Secure Web-Based Applications for Microsoft® Windows 2000 (Redmond: Microsoft Press, July 2000), p. 109. For additional information on authentication methods in IIS, click the article numbers below to view the articles in the Microsoft Knowledge Base: Q264921 INFO: How IIS Authenticates Browser Clients Q229694 How to Use the IIS Security 'What If' Tool For more information on Kerberos, see the following articles in the Microsoft Knowledge Base: Q217098 Basic Overview of Kerberos User Authentication Protocol in Windows 2000 Q266080 Answers to Frequently Asked Kerberos Questions Q231789 Local Logon Process for Windows 2000 Additional query words: iis 5 ====================================================================== Keywords : Technology : kbiisSearch kbiis500 Version : :5.0 Issue type : kbinfo ============================================================================= 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 2001.