Execution Triggers

Viruses do not always execute immediately after infecting a target device. There is often an ``incubation period'' in which the virus sits dormant, waiting for a specific time, key sequence, or other pre-ordained initiator. The inclusion of an incubation period increases the difficulty of determining exactly how or when the system was infected. As more system activity takes place over time, the ability to backtrack to the point of infection becomes difficult if not impossible.