It sounds like something from a sci-fi movie: technology acting on its own, without human guidance, to attack computer systems. But this isn't a scene from a movie — it happened this summer, when the tech company Hugging Face detected an attack on its systems. The attacker stole data and performed other unauthorized activity over several days. It was "different from anything we had handled before," Hugging Face said on its website. Hugging Face alerted the FBI. As it turned out, it wasn't the work of a human hacker or a foreign adversary. Agents powered by artificial intelligence were the...