Viral replication detection using a counter virus

The present invention relates to a parasitic counter virus for detection of previously unseen malicious computer viruses through the infection of such computer viruses. The invention comprises a counter virus agent for detecting viral infection of a computer system. The agent identifies potential host files for the agent within the computer system; and controls replication of the agent within the host files to maintain the agent at a pre-determined population level. When instantiated within one of the host files, the agent determines the population level of the agent within the computer system; and, responsive to the population level exceeding the pre-determined population level, indicates possible viral infection of the computer system.