User Authentication

Security Issues for Middle-Tier Applications

There are a number of security issues for middle-tier applications:

Accountability: The database server must be able to distinguish between the actions of a client and the actions an application takes on behalf of a client. It must be possible to audit both kinds of actions.

Differentiation: The database server must be able to distinguish between a web server transaction, a web server transaction on behalf of a browser client, and a client accessing the database directly.

Least privilege: Users and middle tiers should be given the fewest privileges necessary to do their jobs.

Identity Issues in a Multitier Environment

Multitier authentication maintains the identify of the client through all tiers of the connection. This is necessary because if the identity of the originating client is lost, it is not possible to maintain useful audit records. In addition, it is not possible to distinguish operations performed by the application server on behalf of the client from those done by the application server for itself.

Restricted Privileges in a Multitier Environment

Privileges in a multitier environment are limited to what is necessary to perform the requested operation.

Client Privileges Client privileges are as limited as possible in a multitier environment. Operations are performed on behalf of the client by the application server.

Application Server Privileges Application server privileges in a multitier environment are limited so that the application server cannot perform unwanted or unneeded operations while performing a client operation.

See Also: Oracle9i Database Administrator’s Guide for more information about multitier authentication

Authentication by the Secure Socket Layer Protocol

The Secure Socket Layer (SSL) protocol is an application layer protocol. It can be used for user authentication to a database, independent of global user management in Oracle Internet Directory. That is, users can use SSL to authenticate to the database without implying anything about their directory access. However, if you

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User Authentication

wish to use the enterprise user functionality to manage users and their privileges in a directory, the user must use SSL to authenticate to the database. A parameter in the initialization file governs which use of SSL is expected.

Authentication of Database Administrators

Database administrators perform special operations (such as shutting down or starting up a database) that should not be performed by normal database users. Oracle provides a more secure authentication scheme for database administrator usernames.

You can choose between operating system authentication or password files to authenticate database administrators.

Figure 22–3 illustrates the choices you have for database administrator authentication schemes, depending on whether you administer your database locally (on the same machine on which the database resides) or if you administer many different database machines from a single remote client.

Figure 22–3 Database Administrator Authentication Methods

Use a password file

On most operating systems, operating system authentication for database administrators involves placing the operating system username of the database administrator in a special group (on UNIX systems, this is the dba group) or giving that operating system username a special process right.

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