Direct Memory Access (DMA) attacks. Risks, techniques, and mitigations in hardware hacking

This report examines DMA attacks across physical and remote vectors and demonstrates a PCIe-based proof of concept using PCILeech and Squirrel Screamer to achieve kernel-level memory access on a Linux system, enabling filesystem modification and credential/rooting scenarios. It highlights risks to enterprise and cloud/RDMA environments (including pre-boot exposures and past cases like macOS FileVault) and outlines mitigations such as disabling or controlling DMA-capable ports, enforcing IOMMU/Kernel DMA Protection, and strengthening BIOS/UEFI boot protections.