Zone Labs' easy-to-use ZoneAlarm Internet Security Suite comes with an excellent software firewall that deserves to be accompanied by a better antivirus and antispyware engine.

Zone Labs has its roots in firewalls, a history that explains why its suite's firewall was among the best we tested for our latest security suite roundup. It passed all of our tests involving network threats both inside and outside the PC. It was also the only firewall to pass 17 out of 17 leak tests, which determine whether a piece of malware can sneak information out of a PC without tripping the firewall.

The $70 (as of 4/15/06) Zone Labs package includes a version of CA's antivirus and antispyware scanner that is older than what CA uses in its own suite. (Zone Labs says the scanner should be updated in June.) This engine did not perform well in our virus and spyware tests. Detecting only 30 percent of back doors, 49 percent of bots, and 31 percent of Trojan horses in AV-Test.org's collection of malware, it came in last among the ten suites we tried. It ranked second to last (above Microsoft's suite) in heuristics, the ability to detect unknown malware based on similarities to previously detected threats. It also ranked last in adware detection, and found less malware than CA's suite did in runtime compressed program files, ranking second to last (ahead of Aluria's suite). On the other hand, this suite did well in malware clean-up tests, disinfecting all worms except for Sober.I and cleaning up most resulting Registry and Hosts-file changes.

ZoneAlarm Internet Security has a behavior-based malware detection feature called the OSFirewall, which we were not able to test. It monitors activity on your PC and blocks files that behave suspiciously. This type of protection might serve you well in the critical hours between the time a malware writer unleashes a new virus outbreak and the time a security software company can deploy an update to stop it.

Additional features include antispam and antifraud capabilities, Wi-Fi security protection, privacy settings, and parental controls. Its interface is easy to use, although the malware alert dialog boxes I encountered would have benefited from providing more context about potential threats--for example, an alert announcing 'the file is-4DGAE.tmp is trying to launch C:\WINDOWS\explorer.exe' isn't clear.

ZoneAlarm Internet Security's features and firewall are top-notch, but they need antivirus and antispyware protection to match.

Narasu Rebbapragada