Guidelines for Securing the Network Connection

Protecting the network and its traffic from inappropriate access or modification is the essence of network security. You should consider all paths the data travels, and assess the threats on each path and node. Then, take steps to lessen or eliminate those threats and the consequences of a security breach. In addition, monitor and audit to detect either increased threat levels or penetration attempts.

To manage network connections, you can use Oracle Net Manager. For an introduction to using Oracle Net Manager, see Oracle Database 2 Day DBA. See also Oracle Database Net Services Administrator's Guide.

The following practices improve network security:

1. Monitor listener activity.

   You can monitor listener activity by using Oracle Enterprise Manager Database Control. In the Database Control home page, under General, click the link for your listener. The Listener page appears. This page provides detailed information, such as the category of alert generated, alert messages, when the alert was triggered, and so on. This page provides other information, such as performance statistics for the listener.

2. Prevent online administration by requiring the administrator to have the write privilege on the listener password and on the listener.ora file on the server:

   1. Add or modify this line in the listener.ora file:

      ADMIN_RESTRICTIONS_LISTENER=ON
      

   2. Use RELOAD to reload the configuration.

   3. Use SSL when administering the listener by making the TCPS protocol the first entry in the address list, as follows:

      LISTENER=
        (DESCRIPTION=
          (ADDRESS_LIST=
            (ADDRESS=
              (PROTOCOL=tcps)
              (HOST = shobeen.us.example.com)
              (PORT = 8281)))
      

      To administer the listener remotely, define the listener in the listener.ora file on the client computer. For example, to access listener USER281 remotely, use the following configuration:

      user281 =
        (DESCRIPTION =
          (ADDRESS =
            (PROTOCOL = tcps)
            (HOST = shobeen.us.example.com)
            (PORT = 8281))
          )
        )
      

   For more information about the parameters in listener.ora, see Oracle Database Net Services Reference.

3. Do not set the listener password.

   Ensure that the password has not been set in the listener.ora file. The local operating system authentication will secure the listener administration. The remote listener administration is disabled when the password has not been set. This prevents brute force attacks of the listener password.

   Remember that the listener password has been deprecated in this release, and will not be supported in the next release of Oracle Database.

4. When a host has multiple IP addresses associated with multiple NIC cards, configure the listener to the specific IP address.

   This enables the listener to monitor all the IP addresses. You can restrict the listener to monitor a specific IP address. Oracle recommends that you specify the specific IP addresses on these types of computers, rather than enabling the listener to monitor all IP addresses. Restricting the listener to specific IP addresses helps to prevent an intruder from stealing a TCP end point from the listener process.

5. Restrict the privileges of the listener, so that it cannot read or write files in the database or the Oracle server address space.

   This restriction prevents external procedure agents spawned by the listener (or procedures executed by an agent) from inheriting the ability to perform read or write operations. The owner of this separate listener process should not be the owner that installed Oracle Database or executes the Oracle Database instance (such as ORACLE, the default owner).

   For more information about configuring external procedures in the listener, see Oracle Database Net Services Administrator's Guide.

6. Use encryption to secure the data in flight.

   See "Protecting Data on the Network by Using Network Encryption" to learn about how to protect Oracle data over the network. Oracle Database Advanced Security Administrator's Guide describes network encryption in detail.

7. Use a firewall.

   Appropriately placed and configured firewalls can prevent outside access to your databases.

   • Keep the database server behind a firewall. Oracle Database network infrastructure, Oracle Net (formerly known as Net8 and SQL*Net), provides support for a variety of firewalls from various vendors. Supported proxy-enabled firewalls include Gauntlet from Network Associates and Raptor from Axent. Supported packet-filtering firewalls include PIX Firewall from Cisco, and supported stateful inspection firewalls (more sophisticated packet-filtered firewalls) include Firewall-1 from CheckPoint.

   • Ensure that the firewall is placed outside the network to be protected.

   • Configure the firewall to accept only those protocols, applications, or client/server sources that you know are safe.

   • Use a product such as Oracle Connection Manager to multiplex multiple-client, network sessions through a single network connection to the database. It can filter using the source, destination, and host name. This product enables you to ensure that connections are accepted only from physically secure terminals or from application Web servers with known IP addresses. (Filtering using the IP address alone is not enough for authentication, because it can be falsified.)

8. Prevent unauthorized administration of the Oracle listener.

   For more information about the listener, see Oracle Database Net Services Administrator's Guide.

9. Check network IP addresses.

   Use the Oracle Net valid node checking security feature to allow or deny access to Oracle server processes from network clients with specified IP addresses. To use this feature, set the following sqlnet.ora configuration file parameters:

   tcp.validnode_checking = YES
   
   tcp.excluded_nodes = {list of IP addresses}
   
   tcp.invited_nodes = {list of IP addresses}
   

   The tcp.validnode_checking parameter enables the feature. The tcp.excluded_nodes and tcp.invited_nodes parameters deny and enable specific client IP addresses from making connections to the Oracle listener. This helps to prevent potential Denial of Service attacks.

   You can use Oracle Net Manager to configure these parameters. See Oracle Database Net Services Administrator's Guide for more information.

10. Encrypt network traffic.

    If possible, use Oracle Advanced Security to encrypt network traffic among clients, databases, and application servers. For an introduction to Oracle network encryption, see "Protecting Data on the Network by Using Network Encryption". For detailed information about network encryption, see Oracle Database Advanced Security Administrator's Guide.

11. Secure the host operating system (the system on which Oracle Database resides).

    Secure the host operating system by disabling all unnecessary operating system services. Both UNIX and Windows platforms provide a variety of operating system services, most of which are not necessary for typical deployments. These services include FTP, TFTP, TELNET, and so forth. Be sure to close both the UDP and TCP ports for each service that is being disabled. Disabling one type of port and not the other does not make the operating system more secure.