WebSphere DMZ Secure Proxy Server for IBM WebSphere Application Server

We can use the DMZ Secure Proxy Server for IBM WebSphere Application Server to provide a secure platform for the proxy server.

The DMZ Secure Proxy Server for IBM WebSphere Application Server installation enables you to install the proxy server in the demilitarized zone (DMZ), while reducing the security risk that might occur if you choose to install an application server in the DMZ to host a proxy server. The risk is reduced by removing any functionality from the application server that is not required to host the proxy servers, but that can pose a security risk. Installing the secure proxy server in the DMZ rather than the secured zone presents new security challenges. However, the secure proxy server is equipped with capabilities to provide protection from these challenges.

The following capabilities are available to harden the security of the DMZ Secure Proxy Server for IBM WebSphere Application Server and to determine the level of security to assign.

• Startup user permissions

  The secure proxy server process can be changed to run as an unprivileged user after startup. Although the secure proxy server must be started as a privileged user, changing the server process to run as an unprivileged user provides additional protection for local operating resources.

• Route considerations

  The secure proxy server can be configured to route requests to target servers based on static routing information or dynamic information. Static routing means that the server obtains the routing information from local flat files. Dynamic routing means that the server obtains the routing information from a Hypertext Transfer Protocol (HTTP) tunnel connection from the proxy server to a server in the secure zone. It is more secure to use static routing as the use of dynamic routing requires an additional connection through the inner firewall. Static routing is only applicable to HTTP requests.

• Administration options

  The secure proxy server does not contain a web container, and therefore is unable to host the administrative console. It is better to not have a web container on a DMZ Secure Proxy Server for IBM WebSphere Application Server since hosting application artifacts is considered a security risk and adds an unnecessary footprint to the proxy server. The secure proxy server is installed separately and has several different administrative options that have security implications.

• Error handling

  Custom error pages can be used by the secure proxy server for specific error codes or groups of error codes. A custom error page application can be used to generate error messages or flat custom error page files can be stored locally on the file system and used during run time. Choosing to use flat custom error pages instead of a custom error application provides a higher level of security. Choosing this option limits the code path and eliminates the need for a potentially unauthorized application to be run when an error page is needed.

• Denial of service protection
• Denial of service protection is provided with the inclusion of two properties: Maximum request body buffer chunk size and Maximum response body buffer chunk size. These properties must be tuned to balance the level of protection with the performance overhead that might be experienced if these properties are set incorrectly.

When creating the DMZ Secure Proxy Server for IBM WebSphere Application Server, we can choose any of the default security levels: High, Medium or Low.

• Low DMZ security level
  values. This table describes the settings and default

  Setting	Default value
  Startup permissions	Run as a privileged user
  Routing	Dynamic routing
  Administration	Remote Administration
  Error handling	Local error page handling

• Medium DMZ security level
  default values. This table describes the settings and

  Setting	Default value
  Startup permissions	Run as an unprivileged user
  Routing	Dynamic routing
  Administration	Local Administration
  Error handling	Local error page handling

• High DMZ security level
  values. This table describes the settings and default

  Setting	Default value
  Startup permissions	Run as an unprivileged user
  Routing	Static routing
  Administration	Local Administration
  Error handling	Local error page handling

Important: The High DMZ security level cannot be used for SIP proxy servers, because static routing cannot be used for the SIP proxy server.

In addition to these predefined settings, we can customize the settings to better serve the requirements. If we choose to customize the settings, the DMZ Secure Proxy Server for IBM WebSphere Application Server is assigned a qualitative categorization of the security level called the current security level. Each custom setting has been assigned a value of High, Medium or Low. The current security level is equal to the value of the least secure setting being used. To achieve a current security level of High, only settings assigned the high value can be configured. To achieve a current security level of Medium, only settings with values of High or Medium can be used. A current security level of Low is used if any settings assigned the value of Low are set.

An additional change to enhance the protection for the DMZ Secure Proxy Server for IBM WebSphere Application Server is the switch from a Java Development Kit (JDK) to a Java Runtime Environment (JRE). Switching from a JDK to a JRE removes the inclusion of a compiler on the installation. This change is beneficial because the compiler can possibly be used for malicious purposes in the event of a security breach.

(iseries) No JRE currently is available for i5/OS systems; therefore, a JDK is used. For protection against this type of threat, we can manually remove the tools.jar file from the JDK installation root.

Related tasks

Proxy server setup

Configure a DMZ Secure Proxy Server for IBM WebSphere Application Server using the administrative console