Best of open source in security

Top projects in vulnerability scanning, intrusion prevention, anti-virus, anti-spam, firewalls, VPNs, and security testing

In areas such as CRM software and portals, open source gained a foothold because users were willing to compromise -- less could be more, because the price was right. In security, open source rushed in because commercial vendors fell down on the job. As security problems in the enterprise outstripped the capabilities of commercial solutions, a number of talented security researchers stepped into the breach via the open source model.

From folks such as Renaud Deraison of Nessus to Martin Roesch of Snort, great security tools poured forth to the enterprise. There are now thriving open source security projects in anti-virus, anti-spam, personal and application firewalls, VPNs, IDS/IPS, wireless security, vulnerability assessment, and penetration testing to name but a few.

In network vulnerability assessment, our Bossie winner, Nessus, stands alone. The granddaddy of all security tools, Nessus combines an up-to-the-minute vulnerability engine and testing controls, making it an essential member of the toolbox in both well-funded and cash-strapped security organizations. It tests all aspects of a target including the operating system, ports, services, and applications, and it scores consistently as the top security tool based on professional security tester reviews. Reports can be lengthy, but they're comprehensive.

Nessus shows you where intruders might get in. Snort, which takes our Bossie for intrusion prevention, can stop them from doing so. Snort performs real-time traffic analysis and packet logging. In addition to classic protocol analysis, Snort now also performs content monitoring. Its rules language has evolved light-years beyond the version available when Snort was first released. And like Nessus, Snort is at the top of the heap in community support. The Snort project has spawned a range of add-on projects such as ACID (Analysis Console for Intrusion Databases), SnortSnarf, Swatch, and SnortCenter. These add-ons are needed for reporting and centralized control of multiple Snort boxes; Snort itself is strictly the detection and prevention engine.

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.

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Tom Bowers

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