In the case of anti-virus, one open source solution stands alone, ClamAV. ClamAV was recently purchased by Sourcefire, the owners of Snort. As with most projects on this distinguished list, ClamAV runs on Linux and Unix, and it was designed primarily for e-mail gateways. Virus signature updates are frequent and the detection engine is fast. ClamAV works well with Spamassassin within the MIMEDefang filtering framework for e-mail servers.
Our Bossie winner for anti-spam is the ubiquitous Spamassassin. Powerful, extensible, and effective, Spamassassin uses a trainable neural network engine to identify spam and minimize false positives, in addition to the classic techniques of blacklisting and Bayesian filtering.
Snatching our Bossie for best firewall is IPCop. IPCop is a complete Linux distribution with the sole purpose of network protection. Think of it as a Linux computer with one task: imposing security policies on network traffic. A competing project, SmoothWall, similarly turns any old PC into a high-functioning firewall appliance, but the Web management interface of IPCop is a bit more refined and thus edged out its competition.
Not to be outdone by the private sector, the exceptionally talented folks at the NSA created a superior application firewall called SELinux. The special sauce of this Linux distribution is a mandatory access control architecture for the OS kernel and major subsystems that keeps every process in check, ensuring that the action of one process cannot flow into another. Even the superuser is placed in isolation. A worthy competitor is Novell's open source AppArmor project, an easy-to-configure application firewall aimed exclusively at Suse distributions. SELinux continues to be better supported by the security community, and it forms the basis for a flexible security solution (versus a simple secure operating system). SELinux takes the Bossie.
OpenVPN, our Bossie winner for best SSL VPN, is the open source champion of secure connectivity. OpenVPN simply outshines its competition. It can be used to secure site to site links, remote access connections, and Wi-Fi networks, providing load balancing and fail-over capabilities. It runs on a wide range of operating systems and is supported by numerous open source projects and commercial products. And OpenVPN supports all ciphers and key sizes supported by OpenSSL, giving it tremendous flexibility.
Although not an application per se, the OSSTMM (Open Source Security Testing Methodologies Manual) is a phenom in the security world. The OSSTMM project provides an entire testing framework for security throughout the enterprise, including physical security, information security, Internet and wireless security, even security against fraud and social networking attacks. The OSSTMM provides a method for quantifying risk and an excellent foundation for security testing best practices. The project offers testing templates, intense community support, and a first-rate architect in Pete Herzog, scoring our Bossie for security testing best practices.