A team of researchers have discovered a new security vulnerability involving the Thunderbolt data transfer specification. They’ve dubbed the vulnerability “Thunderclap” and it affects systems that use the Thunderbolt interface.
The way the vulnerability works is by taking advantage of direct-memory-access (DMA) that Thunderbolt devices have. For context, DMA allows Thunderbolt devices to read and write data on a system’s memory without permission from the operating system.
This level of access is usually only granted to internal components, such as GPUs. But with the Thunderbolt interface – used by USB-C connectors – capable of replicating those functions when plugged in externally, the interface is given the same level of access. This, in turn, makes it vulnerable to Thunderclap.
Fortunately, fixes have already been rolled out. Apple has fixed the specific vulnerability exploited by the researchers in macOS 10.12.4, while Windows 10 devices using version 1803 or newer should also be safe from Thunderclap. All that said, it’s still a good reminder to not plug your USB-C devices into chargers that you don’t trust or look absolutely questionable.