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Securing RDS Applications

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Microsoft Internet Explorer Security Issues

With new security enhancements added to Microsoft® Internet Explorer, some ADO and RDS objects are restricted to running only in a "safe" mode environment. This requires that you are aware of these issues, including different zones, security levels, restrictive behavior, unsafe operations, and customized security settings.

Security and Your Web Server

If you use the RDSServer.DataFactory object on your Internet Web server, remember that doing so creates a potential security risk. External users who obtain valid data source name (DSN), user ID, and password information could write pages to send any query to that data source. If you want more restricted access to a data source, one option is to unregister and delete the RDSServer.DataFactory object (msadcf.dll), and instead use custom business objects with hard-coded queries.

For more information on the security implications of using the RDSServer.DataFactory object, see the Microsoft Security Bulletin MS99-025 on the Microsoft Security Web site.

Client Impersonation and Security

If the Password Authentication property for your IIS Web server is set to Windows NT Challenge/Response authentication (for Windows NT 4.0) or to Integrated Windows authentication (for Windows 2000), then business objects are invoked under the client's security context. This is a new feature in RDS 1.5 that allows Client Impersonation over HTTP. When working in this mode, the logon to the Web server (IIS) is not anonymous but uses the user ID and password that the client computer is running under. If the ODBC DSNs are set up to use Trusted Connection, then access to databases, such as SQL Server, also happens under the client's security context. But this only works if the database is on the same computer as the IIS; the client credentials cannot be carried over to yet another computer.

For example, a client, John Doe, with userid="JohnD" and password="secret" is logged on to a client computer. He runs a browser-based application that needs to access the RDSServer.DataFactory object to create a Recordset by executing an SQL query on the "MyServer" computer running IIS. MyServer, a system running Windows NT Server 4.0, is set up to use Windows NT Challenge/Response authentication, its ODBC DSN has "Use Trusted Connection" selected, and the server also contains the SQL Server data source. When a request is received on the Web server, it asks the client for the user ID and password. Thus, the request is logged on MyServer as coming from "JohnD"/"Secret" instead of IUSER_MyServer (which is the default when Anonymous Password Authentication is on). Similarly, when logging on to SQL Server, "JohnD"/"Secret" is used.

Consequently, the IIS Windows NT Challenge/Response authentication mode allows HTML pages to be created without the user being explicitly prompted for the user ID and password information needed to log on to the database. If the IIS Basic Authentication were being used, then this also would be required.

Password Authentication

RDS can communicate with an IIS Web server running in any one of the three Password Authentication modes: Anonymous, Basic, or NT Challenge/Response authentication (called Integrated Windows authentication in Windows 2000). These settings define how a Web server controls access through it, such as requiring that a client computer have explicit access privileges on the NT Web server.