AV-Test Institute tested several antivirus tools that proved wildly effective against zero-day threats, while others failed miserably.

For two months, AV-Test's researchers exposed each product's zero-day malware protection to newly-discovered malware.

Ten of the 25 tested security products achieved 100% protection in both months of testing. Among them: Bitdefender Internet Security (2014), Kaspersky Internet Security (2014), and Norton Internet Security (2014).

Included in this test for the first time, Check Point's ZoneAlarm managed 99 percent in March and 100 percent in April, as did Panda's free Cloud Antivirus.

In other tests, Kaspersky managed a rarely-seen total score of 18 points, with a perfect six of six in all three categories. Avira managed a total of 17.5, Bitdefender, McAfee, and Qihoo also earned 17.5 points.