What we may think are obsolete remain an integral part of defence in depth strategies. An antivirus system using heuristics and updated signatures provides another barrier between good and bad. Although viruses do not get the attention given modern threats, that does not negate their existence. Legacy viruses may be modified to deliver new threats if we let our guard down. They are like influenza, mutating year after year and finding new ways to remain deadly. We cannot afford to ignore them. Consider why spam emails supposedly from despot dictators still circulate globally despite being widely known: They still work.