(Kevin Beaver, CISSP) Even with the common vulnerabilities I've talked about in the past, Linux is a solid operating system (OS) that stands up well to security tests. This doesn't mean, however, that you should let your guard down. Over time, configuration tweaks, third-party software and human intervention tend to change the security posture of once-secure Linux systems. This will inevitably lead, at best, to dings noted on vulnerability-assessment or audit reports.

But there is a way to establish a solid Linux security foundation and set your business up for future success, and that is hardening your Linux systems using Bastille UNIX, an open source project led by Jay Beale.

Formerly named Bastille Linux, the graphical user interface (GUI)-based Bastille UNIX steps you through the OS-hardening process for Debian, Gentoo, Mandriva, Red Hat and SUSE Linux distributions, as well as HP-UX and Mac OS X. Its intuitive question-and-answer approach allows you to lock your system down without having to worry about fat-fingering or configuring something incorrectly along the way. Bastille is not just a hardening program -- it's also a great learning aid, something that could be used to teach classes.

Bastille UNIX is an easy download and even easier to run. There are several system hardening categories you can choose from, including patches, file permissions, account security, domain name systems and more. As shown in Figure 1, Bastille prompts users with specific questions and offers detailed explanations to ensure that the effects of each action will be understood.