German computer magazine C'T claims the effectiveness of antivirus software is dropping and that more and more malware is slipping past these barriers:
In standard tests, the virus scanners have to recognize known malware. When tested by c't with more than a million pests that have appeared over the last six months, Avira Antivir and Gdata Antivirus 2008 identified over 99 per cent by their signatures, but Avast, AVG Anti Malware and BitDefender also achieved very good results.
For real protection, however, in view of the flood of new malware, the way these programs cope with new and completely unfamiliar attacks is more important. And that's where almost all of the products performed significantly worse than just a year ago. The typical recognition rates of their heuristics fell from approximately 40-50 per cent in the last test - at the beginning of 2007 - to a pitiful 20-30 per cent. Only NOD32, with 68 per cent, still delivered a good result, while BitDefender, with 41%, could be called satisfactory.
One reason why almost all of the scanners did worse in these heuristics tests than a year ago is certainly the professionalization of the malware scene: more time and energy are being invested in slipping this stuff past protective software. What is worrying, however, is the fact that recognition rates of virus variants created experimentally by c't also fell significantly. Virtually all of the scanners missed variants of viruses they had identified a year earlier.