New UEFI Flaw Enables Early-Boot DMA Attacks on ASRock, ASUS, GIGABYTE, MSI Motherboards

"UEFI and IOMMU are designed to enforce a security foundation and prevent peripherals from performing unauthorized memory accesses, effectively ensuring that DMA-capable devices can manipulate or inspect system memory before the operating system is loaded. The vulnerability, discovered by Nick Peterson and Mohamed Al-Sharifi of Riot Games in certain UEFI implementations, has to do with a discrepancy in the DMA protection status. While the firmware indicates that DMA protection is active, it fails to configure and enable the IOMMU during the critical boot phase."

""This gap allows a malicious DMA-capable Peripheral Component Interconnect Express (PCIe) device with physical access to read or modify system memory before operating system-level safeguards are established," the CERT Coordination Center (CERT/CC) said in an advisory. "As a result, attackers could potentially access sensitive data in memory or influence the initial state of the system, thus undermining the integrity of the boot process." Successful exploitation of the vulnerability could allow a physically present attacker to enable pre-boot code injection on affected systems running unpatched firmware and access or alter system memory via DMA transactions, much before the operating system kernel and its security features are loaded."

Certain ASRock, ASUSTeK Computer, GIGABYTE, and MSI motherboard models contain a UEFI implementation flaw that enables early-boot DMA attacks. UEFI and IOMMU are intended to prevent unauthorized peripheral memory accesses, but some firmware reports DMA protection as active while failing to configure or enable the IOMMU during the critical boot phase. That discrepancy allows a malicious PCIe device with physical access to read or modify system memory before operating system safeguards are in place. Successful exploitation can enable pre-boot code injection, access to sensitive memory contents, and compromise of the system boot integrity. Multiple CVEs identify affected chipsets and models.

Read at The Hacker News