Over the past 11 months, the processors running our computers, and in some cases phones, have succumbed to a host of attacks. Bearing names such as Meltdown and Spectre, BranchScope, TLBleed, and Foreshadow, the exploits threaten to siphon some of our most sensitive secrets—say passwords or cryptographic keys—out of the silicon microarchitecture in ways that can't be detected or stopped by traditional security defenses. On Friday, researchers disclosed yet another leak that has already been shown to exist on a wide range of Intel chips and may also affect other makers, too.

PortSmash, as the new attack is being called, exploits a largely overlooked side-channel in Intel's hyperthreading technology. A proprietary implementation of simultaneous multithreading, hyperthreading reduces the amount of time needed to carry out parallel computing tasks, in which large numbers of calculations or executions are carried out simultaneously.