Overlook hot fixes and security packs and installation security can fly out the window, according to Microsoft...
security expert Joern Wettern. During Microsoft's recent TechEd 2002 conference in New Orleans, Wettern detailed the dos and don'ts to securely install Microsoft's Internet Security and Acceleration (ISA) Server, a full firewall and proxy server.
- Do think about what the role of ISA Server should be within a domain, said Wettern. "Domain membership is required only for arrays and user-based rules," he said. Perhaps, then you'll just want to install it as a regular member server.
- Do create a separate domain or forest if you want an array. Keep in mind, however, that will only slightly increase security and will be at a large software and hardware cost. A separate forest can make sense in a perimeter network, or demilitarized zone (DMZ). "It makes sense to have a separate Active Directory forest in a DMZ, but don't make it related to the internal AD forest," said Wettern.
- Don't forget to disconnect the computer from the Internet. "That sounds so simple," Wettern said, "but you'd be surprised how many people forget."
- Do install Windows 2000 Server and only the required components. Do figure out what type of server it will be. Ask yourself: Will it be a Web server or mail server or something else?
- Do install the latest service packs and security rollup packages. Wettern recommended HFNetChk or Security Baseline Analyzer to find the needed hot fixes.
- Do disable any unnecessary services. What is unnecessary depends on the specific network environment and how the server is configured, said Wettern.
- Do remove bindings. Unbind all services from external interfaces. Keep only TCP/IP enabled.
- Do install only the required components and review the local address table (LAT) before continuing. The LAT records which subnets or ranges are on the internal network. This is most important because the LAT can contain the wrong IP addresses and create a security risk, said Wettern.
- Do install service pack one (SP1) and any applicable hot fixes.
- Don't forget that "after ISA Server is installed, it blocks all traffic until you allow it," Wettern said.
- In terms of additional security, don't forget the network infrastructure. Do use a filtering router as your first line of defense and to defeat DoS attacks, said Wettern.
- Do use third party add-ins for virus protection and intrusion detection.