CVE-2014-4859 in EDK2
Summary
by MITRE
Integer overflow in the Drive Execution Environment (DXE) phase in the Capsule Update feature in the UEFI implementation in EDK2 allows physically proximate attackers to bypass intended access restrictions via crafted data.
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Analysis
by VulDB Data Team • 04/22/2023
The vulnerability identified as CVE-2014-4859 represents a critical integer overflow condition within the UEFI implementation of the Intel EDK2 firmware development kit. This flaw specifically manifests during the Drive Execution Environment phase, which is a crucial component of the Unified Extensible Firmware Interface specification responsible for executing firmware updates and managing system boot processes. The vulnerability exists within the Capsule Update feature, which serves as the mechanism for delivering firmware updates to UEFI-capable systems. The integer overflow occurs when processing crafted data structures during the capsule update process, creating a scenario where malicious inputs can manipulate the firmware's memory management and access control mechanisms. This vulnerability is particularly concerning because it allows attackers with physical proximity to a target system to bypass intended access restrictions, effectively undermining the security controls that should protect against unauthorized firmware modifications.
The technical implementation of this vulnerability stems from improper input validation within the DXE phase of UEFI firmware execution. During capsule processing, the firmware fails to properly validate integer values when calculating buffer sizes or memory allocation parameters. When attackers provide maliciously crafted data containing oversized or negative integer values, the firmware's arithmetic operations overflow, causing unexpected behavior in memory management routines. This overflow condition can result in buffer overflows, memory corruption, or privilege escalation scenarios that allow attackers to manipulate firmware execution paths. The vulnerability is classified under CWE-190 as an integer overflow or wraparound, which represents a fundamental flaw in how the firmware handles numeric data types during critical system operations. The specific context of this vulnerability within the UEFI framework means that successful exploitation could lead to complete system compromise, as firmware-level modifications can persist across reboots and are typically immune to standard operating system security controls.
The operational impact of CVE-2014-4859 extends far beyond simple privilege escalation, as it fundamentally undermines the integrity and security of the entire system boot process. Attackers with physical access can leverage this vulnerability to install malicious firmware updates that persist across system reboots, potentially creating backdoors or disabling security features. The attack vector's requirement for physical proximity makes this vulnerability particularly dangerous in environments where attackers might have access to target systems, such as in corporate settings, data centers, or supply chain scenarios. The implications for enterprise security are severe, as this vulnerability could enable attackers to compromise systems at the firmware level, bypassing traditional endpoint protection mechanisms and operating system security controls. This type of attack aligns with ATT&CK technique T1068, which covers local privilege escalation, and T1542, which addresses spoofing of system processes. The vulnerability's exploitation could lead to persistent malware installations that are extremely difficult to detect and remove, as these modifications occur at a level below the operating system's normal security monitoring capabilities.
Mitigation strategies for CVE-2014-4859 must address both immediate remediation and long-term firmware security practices. The primary solution involves updating to patched versions of EDK2 firmware implementations that properly validate integer inputs and prevent overflow conditions during capsule processing operations. Organizations should implement firmware update policies that ensure all systems receive security patches promptly, particularly in environments where physical security controls are insufficient. Hardware-based security features such as Platform Trust Technology, Secure Boot implementations, and firmware integrity monitoring systems should be deployed to detect unauthorized modifications. Additionally, implementing strict access controls and physical security measures to prevent unauthorized access to systems during update processes is essential. The vulnerability highlights the importance of comprehensive firmware security practices, including regular firmware audits, vulnerability assessments, and supply chain security controls. Organizations should also consider implementing firmware-level monitoring systems that can detect anomalous behavior patterns consistent with exploitation attempts, as traditional network-based security controls may be insufficient to protect against firmware-level attacks. This vulnerability serves as a reminder of the critical importance of securing firmware components in modern computing environments, as these low-level systems form the foundation upon which all other security controls operate.