CVE-2023-43608 in Buildroot
Summary
by MITRE • 12/05/2023
A data integrity vulnerability exists in the BR_NO_CHECK_HASH_FOR functionality of Buildroot 2023.08.1 and dev commit 622698d7847. A specially crafted man-in-the-middle attack can lead to arbitrary command execution in the builder.
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Analysis
by VulDB Data Team • 12/05/2023
The vulnerability identified as CVE-2023-43608 represents a critical data integrity flaw within the Buildroot embedded Linux distribution framework. This issue specifically affects the BR_NO_CHECK_HASH_FOR functionality, which is designed to bypass hash verification checks during the build process. The vulnerability stems from inadequate validation mechanisms that fail to properly authenticate the integrity of downloaded packages and components. When this functionality is enabled, the build system becomes susceptible to man-in-the-middle attacks where malicious actors can inject compromised artifacts without triggering the expected hash verification processes. The flaw exists in Buildroot versions 2023.08.1 and the development commit 622698d7847, indicating this vulnerability has been present in recent releases and potentially affects numerous embedded systems relying on this build framework.
The technical implementation of this vulnerability exploits the trust model within the Buildroot build environment where hash verification is selectively disabled through the BR_NO_CHECK_HASH_FOR configuration option. When this option is activated, the system accepts packages without validating their cryptographic hashes against expected values, creating an attack surface where adversaries can substitute legitimate components with malicious ones. The vulnerability operates at the supply chain level, targeting the integrity of package downloads and build artifacts. An attacker positioned in the network path between the build system and package repositories can intercept and modify downloads, replacing original packages with compromised versions that execute arbitrary commands during the build process. This represents a classic supply chain attack vector that undermines the fundamental security assumptions of the build environment.
The operational impact of CVE-2023-43608 extends beyond simple command execution capabilities to encompass complete system compromise of embedded devices built using vulnerable Buildroot configurations. When an attacker successfully exploits this vulnerability, they can inject malicious code into the build process that persists in the final firmware images, potentially affecting millions of devices that rely on Buildroot for their embedded operating systems. The vulnerability affects various embedded platforms including IoT devices, network equipment, and industrial control systems where Buildroot is commonly deployed. The implications are particularly severe because the compromised build process can silently introduce backdoors, rootkits, or other persistent malware that becomes embedded in the final product, making detection extremely difficult. This vulnerability directly maps to CWE-347, which addresses improper certificate validation, and aligns with ATT&CK technique T1583.001 for developing capabilities and T1059.001 for command and scripting interpreter, as the attack chain involves both supply chain compromise and post-compromise execution.
Mitigation strategies for CVE-2023-43608 require immediate action to disable the BR_NO_CHECK_HASH_FOR functionality in all affected Buildroot configurations. Organizations should implement mandatory hash verification across all build processes and ensure that cryptographic signatures are validated for all downloaded components. The recommended approach includes upgrading to patched versions of Buildroot where this functionality has been properly secured or implementing additional verification layers that independently validate package integrity. Security teams must also establish monitoring mechanisms to detect unauthorized changes to build configurations and implement network-level controls to prevent man-in-the-middle attacks during package downloads. Additionally, organizations should conduct comprehensive audits of their embedded build environments to identify any systems using vulnerable configurations and ensure that all build artifacts undergo strict integrity verification before deployment. The vulnerability highlights the importance of maintaining secure supply chain practices and implementing defense-in-depth strategies that protect against both direct and indirect attack vectors targeting the build infrastructure.