Windows 10 and 8.1 PCs could be vulnerable to Direct Memory Access (DMA) attacks. Microsoft introduced protections against DMA attacks in Windows 8 and Windows 10. Microsoft admitted last week that older, non-PCI buses such as 1394 and CardBus are still vulnerable. An upcoming Windows 10 Insiders Build version will include a patch that will improve the protection against such attacks. Security expert Sami Laiho demoed one such attack via a FireWire port at the Microsoft Ignite conference last year.
Source: https://www.bleepingcomputer.com/news/security/some-windows-10-devices-still-exposed-to-dma-attacks-that-can-steal-bitlocker-keys/