A wall wart is a small plug-in AC-to-DC power adapter that sits directly in a mains outlet and feeds low-voltage power to consumer electronics, routers, toys, and lab gear. The nickname comes from its bulky shape and the way it protrudes from the wall.
In cyber security, wall warts matter because power is part of the trust boundary. A bad, counterfeit, or poorly regulated adapter can cause unstable behavior that looks like a software bug, damage hardware, or break a test setup. Attackers can also hide extra electronics inside a charger-sized enclosure, turning a seemingly ordinary adapter into a malicious or compromised device. Defenders and engineers watch for these risks by checking voltage, current, isolation, and consistency under load, especially when validating prototype systems or USB-C power setups. In practice, the humble wall wart is often the first place where power integrity, device reliability, and physical security meet.