The effectiveness of antivirus products has declined, according to tests by German testing outfit AV-Test.org.
AV-Test put 25 antivirus products for home users and eight corporate endpoint protection software applications through their paces in November and December 2012.
Only an average of 92 per cent of the zero-day attacks were blocked during the tests, it said, a result that suggests that one out of 10 malware attacks succeeded. The products were able to clean 91 per cent of the infected systems, however, only 60 per cent could be put back in a condition similar to the pre-infection state, the firm said.
The tests were carried out on Windows 7 (SP1, 64-bit) machines. The firm said that three of the 25 consumer antivirus products failed to make the grade, including Microsoft Security Essentials and products from PC Tools and AhnLabs.
The eight corporate products came out better, but even so Microsoft Forefront Endpoint Protection flunked the exam after scoring protection against zero-day malware of just 78 per cent in the December tests (although this was an improvement on its score of 67 per cent in November).
Andreas Marx, chief exec of AV-Test, said: "More products than usual had difficulties [meeting] our high standards and therefore failed to receive the AV-Test certification."
The overall results of the test are far better than those obtained from a controversial set of tests run by Imperva in November, which concluded that most antivirus software detects less than 5 per cent of new malware.
Imperva's antivirus test used VirusTotal, but detractors argue that the online service is not designed to determine whether an antivirus product actually blocks a threat since it only looks at whether a signature is on file, not at other lines of defence. VirusTotal itself describes this practice as a "bad idea". The use of VT as a testing tool and other criticisms of Imperva's study are summarised at some length by David Hartley of Eset, an antivirus supplier, here.