Creeper (1971) is widely considered the first malware in history. It spread across the ARPANET, printing a message to the console of infected systems but causing no actual harm.
The response came in 1972 with Reaper, the first anti-malware software. Yet Reaper propagated using the exact same technique as Creeper, moved autonomously from system to system, and executed code without the owner’s explicit consent. Its only distinction was a “beneficial” payload: it deleted Creeper, and eventually deleted itself.
This blurs the line between malware and anti-malware. When the delivery mechanism, propagation method, and autonomous behaviour are identical, the classification depends solely on intent and perception. What is defended as a remedy in one context could be prosecuted as unauthorised access in another.