**ASRock, ASUS, GIGABYTE, MSI Boards Vulnerable to Pre-Boot Memory Attacks**

Researchers have discovered a critical vulnerability in the Unified Extensible Firmware Interface (UEFI) of select motherboards from ASRock, ASUS, GIGABYTE, and MSI. The flaw exposes systems to pre-boot Direct Memory Access (DMA) attacks, bypassing Input/Output Memory Management Unit (IOMMU) protections.

UEFI is the modern firmware standard that initializes hardware and starts the operating system during boot, replacing legacy BIOS. It runs before the OS loads and has high privileges, making it a critical security boundary. IOMMU, on the other hand, is a hardware feature that controls how devices like GPUs or network cards access system memory, preventing unauthorized direct memory access (DMA). Together, UEFI and IOMMU are designed to ensure secure boot and isolate devices.

However, flaws in their implementation can expose systems to powerful early-boot attacks. In this case, a flaw in some UEFI implementations falsely reports DMA protection as active while failing to enable the IOMMU early in the boot process. This gap allows malicious PCIe devices with physical access to read or modify memory before OS protections load.

Researchers Nick Peterson and Mohamed Al-Sharifi of Riot Games discovered the vulnerability, which impacts certain UEFI implementations. "A newly identified vulnerability in some UEFI-supported motherboard models leaves systems vulnerable to early-boot DMA attacks across architectures that implement UEFI and IOMMU," reads the advisory published by the CERT Coordination Center (CERT/CC). "Although the firmware indicates that DMA protection is active, it fails to correctly initialize the IOMMU."

Therefore, a malicious PCIe device with physical access can read or modify system memory before the operating system's defenses load. This exposes sensitive data and enables pre-boot code injection on affected systems running unpatched firmware.

**Affected Vendors and Firmware Updates**

ASRock, ASUS, GIGABYTE, and MSI confirmed that some of their motherboards are affected by the vulnerability. The vendors have issued advisories with firmware patch information to fix IOMMU initialization and restore DMA protections.

Users should patch promptly, especially where physical access isn't tightly controlled, to prevent pre-boot DMA attacks and protect system integrity. "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," continues the report.

"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," warns CERT/CC. "In environments where physical access cannot be fully controlled or relied on, prompt patching and adherence to hardware security best practices are especially important."

**Vulnerability Details**

The vulnerabilities that allow bypassing early-boot memory protection are listed below:

* **CVE-2023-XXXX**: A newly identified vulnerability in some UEFI-supported motherboard models leaves systems vulnerable to early-boot DMA attacks across architectures that implement UEFI and IOMMU. * **CVE-2023-YYYY**: Failing to correctly initialize the IOMMU allows malicious PCIe devices with physical access to read or modify system memory before OS protections load.

**Action Required**

Users and admins should promptly apply firmware updates to fix IOMMU initialization and restore DMA protections, monitoring vendor advisories for new patches. "Because the IOMMU also plays a foundational role in isolation and trust delegation in virtualized and cloud environments, this flaw highlights the importance of ensuring correct firmware configuration even on systems not typically used in data centers."

**Stay Informed**

Follow me on Twitter: @securityaffairs and Facebook and Mastodon for the latest news and updates on cybersecurity.