CVE-2019-18913 in Business PCs
Summary
by MITRE
A potential security vulnerability with pre-boot DMA may allow unauthorized UEFI code execution using open-case attacks. This industry-wide issue requires physically accessing internal expansion slots with specialized hardware and software tools to modify UEFI code in memory. This affects HP Intel-based Business PCs that support Microsoft Windows 10 Kernel DMA protection. Affected versions depend on platform (prior to 01.04.02; or prior to 02.04.01; or prior to 02.04.02).
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Analysis
by VulDB Data Team • 02/01/2020
This vulnerability represents a critical pre-boot security flaw that exploits the DMA (Direct Memory Access) capabilities of Intel-based business PCs to enable unauthorized UEFI code execution through open-case attacks. The issue fundamentally undermines the security model of modern computing systems by allowing physical attackers with specialized hardware to bypass traditional security measures that would normally protect the UEFI firmware during system boot processes. The vulnerability specifically targets HP business PCs that support Microsoft Windows 10 Kernel DMA protection, highlighting a significant gap in hardware security implementations that affects systems with UEFI firmware versions prior to 01.04.02, 02.04.01, or 02.04.02 depending on platform architecture. The attack vector requires physical access to internal expansion slots and necessitates the use of specialized tools to modify UEFI code in memory, making it a sophisticated but achievable threat for determined adversaries.
The technical flaw stems from insufficient DMA protection mechanisms during the pre-boot phase of system operation, where the UEFI firmware fails to properly validate memory access requests from peripheral devices. This vulnerability aligns with CWE-1173, which addresses the improper restriction of operations within a single system, and represents a direct exploitation of the DMA attack surface that has been extensively documented in security literature. The issue is particularly concerning because it operates outside the normal operating system security boundaries, allowing attackers to inject malicious code directly into the UEFI firmware before the operating system has any opportunity to enforce security policies. The attack requires physical access to the system's internal components and the use of specialized hardware tools to manipulate memory regions that should normally be protected from unauthorized modification.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it allows attackers to establish persistent backdoors within the system firmware itself. This creates a particularly dangerous threat vector because UEFI-level modifications are extremely difficult to detect and remove, often requiring complete firmware reflash operations that can potentially brick the device. The implications for enterprise security are severe, as attackers could potentially compromise entire fleets of business PCs without requiring network access or traditional attack vectors. Systems that rely on UEFI-based security features for boot integrity validation become completely compromised, undermining the foundation of the system's security infrastructure. The vulnerability affects critical business infrastructure and could enable attackers to maintain long-term access to sensitive corporate environments while evading traditional endpoint protection mechanisms.
Mitigation strategies for this vulnerability must address both the immediate hardware-level issues and the broader security posture of affected systems. Organizations should prioritize firmware updates from HP to ensure systems are running UEFI versions that properly implement DMA protection mechanisms. The implementation of physical security measures such as tamper-evident seals and restricted access to system internals should be considered as part of a comprehensive security strategy. Additionally, system administrators should implement monitoring solutions capable of detecting unauthorized UEFI modifications and establish procedures for regular firmware integrity verification. This vulnerability demonstrates the importance of addressing security concerns at all layers of the computing stack, including the pre-boot environment, and aligns with ATT&CK technique T1014, which covers rootkit and bootkit development. Organizations should also consider implementing hardware security modules and trusted platform modules to provide additional protection against firmware-level attacks. The security community should also be aware that similar vulnerabilities may exist in other vendors' implementations, making this a broader industry-wide concern that requires coordinated response and remediation efforts.