Security specialist PandaLabs has found that 52 per cent of new viruses are only active for 24 hours before becoming passive and harmless.
The reason for this is partly to avoid detection by security systems and to allow the virus to continue to spread.
An older, inactive piece of malicious code can then be utilised to supplement newer types of malware, which is what happened with the Conficker virus and its variants.
PandaLabs says that this is the reason behind the large increase in new threats – from 18 million to 30 million – that it detected over the course of the last year.
“This is a never-ending race which, unfortunately, the hackers are still winning,” said PandaLabs technical director Luis Corrons. “We have to wait until we get hold of the malware they have created to be able to analyze, classify and combat it. In this race, vendors that work with traditional, manual analysis techniques are too slow to vaccinate clients, as the distribution and infection span is very short.”