Reduce permissions to increase DNS security

Every server process you run on your system provides another potential point of compromise. That’s why it’s so often recommended that you turn off unnecessary services on Windows machines and deactivate unneeded daemons on UNIX operating systems.

You can’t simply turn off all services and daemons, however, as the ability to use your operating system environment would be severely crippled if you did. As a result, it becomes necessary to attempt to secure the operation of the server processes you need.

When you provide a server system on which multiple clients rely, that can become even more important. Every one of the systems that connects to your server relies on its security — in effect, trusts it, to some extent.

If your server is compromised, it may then become a vector for attacks on clients that connect to it. When you run a server system, you become responsible not only for the security of that system, but at least in part for the security of every computer that connects to it.

An example of such a case is a UNIX or Linux DNS server. Just like any other server software, the BIND server daemon named process may occasionally be subject to security vulnerabilities that may allow a malicious security cracker to gain unauthorized access to your system. It is thus important to configure your system to minimize the damage a security cracker can do when he or she exploits such a vulnerability.

One way to do so with the named process on UNIX and Linux systems is to ensure that it doesn’t run as the root user. If the process runs as a less privileged user account, the damage it can do when compromised by a malicious security cracker is greatly reduced.

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