CVE-2014-4860 in EDK2
Summary
by MITRE
Multiple integer overflows in the Pre-EFI Initialization (PEI) boot phase in the Capsule Update feature in the UEFI implementation in EDK2 allow physically proximate attackers to bypass intended access restrictions by providing crafted data that is not properly handled during the coalescing phase.
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Analysis
by VulDB Data Team • 04/22/2023
The vulnerability identified as CVE-2014-4860 represents a critical security flaw within the Unified Extensible Firmware Interface implementation in the Intel EDK2 firmware development kit. This issue manifests during the Pre-EFI Initialization phase, specifically within the Capsule Update feature that handles firmware updates through UEFI firmware. The vulnerability stems from improper handling of integer overflow conditions that occur during the coalescing phase of capsule data processing, creating a pathway for attackers to manipulate firmware update mechanisms.
The technical flaw involves integer overflows that occur when processing capsule update data structures during firmware initialization. During the PEI phase, the firmware performs coalescing operations to merge multiple capsule fragments into a single coherent update package. When attackers provide maliciously crafted data with oversized integer values, the firmware fails to properly validate these inputs, leading to arithmetic overflow conditions. These overflow conditions can cause memory corruption and unexpected behavior in the firmware update processing logic, ultimately allowing unauthorized access to restricted firmware update mechanisms.
The operational impact of this vulnerability is significant as it enables physically proximate attackers to bypass intended access controls and potentially execute arbitrary code within the firmware environment. Attackers can craft malicious capsule update payloads that exploit the integer overflow conditions to manipulate the firmware update process, potentially gaining elevated privileges or bypassing authentication mechanisms. This vulnerability undermines the security model of UEFI firmware implementations and can lead to persistent backdoors or complete system compromise through firmware-level attacks.
The vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and demonstrates how such flaws in firmware implementations can create severe security implications. From an ATT&CK framework perspective, this vulnerability maps to techniques involving firmware manipulation and privilege escalation through boot process exploitation. The attack surface is particularly concerning as it targets the earliest phase of system boot, making it difficult to detect and remediate through traditional operating system security measures.
Mitigation strategies should focus on implementing comprehensive input validation and bounds checking within the firmware update processing code. Firmware vendors should ensure proper integer overflow detection mechanisms are in place during the capsule coalescing phase, with explicit checks for data size constraints and memory allocation limits. Regular firmware updates and patches should be deployed to address the underlying integer overflow conditions, while system administrators should monitor for unauthorized firmware modifications and maintain proper physical security controls to prevent proximity-based attacks. The vulnerability highlights the critical need for robust firmware security practices and adherence to secure coding standards throughout the firmware development lifecycle.