CVE-2016-8422 in Android
Summary
by MITRE
An elevation of privilege vulnerability in the Qualcomm bootloader could enable a local malicious application to execute arbitrary code within the context of the kernel. This issue is rated as Critical due to the possibility of a local permanent device compromise, which may require reflashing the operating system to repair the device. Product: Android. Versions: N/A. Android ID: A-31471220. References: QC-CR#979426.
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Analysis
by VulDB Data Team • 10/27/2022
The vulnerability described in CVE-2016-8422 represents a critical security flaw within the Qualcomm bootloader implementation that affects Android devices. This vulnerability resides at the lowest level of the system architecture, specifically within the bootloader component that initializes the device and loads the operating system. The bootloader serves as the first line of defense in the device's security chain, making any compromise of this component particularly dangerous as it can undermine the entire security framework of the device. The issue is classified as an elevation of privilege vulnerability because it allows a malicious application with local access to escalate its privileges to kernel level execution, effectively bypassing all standard security mechanisms that protect the device from unauthorized code execution.
The technical flaw manifests through a weakness in the Qualcomm bootloader's validation and execution processes that permits unauthorized code to be loaded and executed with kernel-level privileges. This typically occurs through improper input validation or insufficient access controls within the bootloader's initialization routines. The vulnerability creates a persistent backdoor that can be exploited by any locally installed malicious application, eliminating the need for external attack vectors or complex exploitation techniques. The kernel-level execution context provides the malicious code with complete control over the device's hardware resources, memory management, and system operations, effectively granting the attacker root access to the entire system. This type of vulnerability directly maps to CWE-254, which addresses security weaknesses in the implementation of access control mechanisms, and aligns with ATT&CK technique T1068, which covers the exploitation of system vulnerabilities for privilege escalation.
The operational impact of this vulnerability is severe and potentially permanent, as it allows for complete device compromise without requiring user interaction or external network connectivity. Once exploited, the malicious code can persist across reboots and system updates, making it extremely difficult to detect and remove. The compromise typically requires complete device reinstallation or reflashing of the operating system to restore proper functionality, which results in complete data loss for the user. This vulnerability affects the fundamental integrity of the Android security model, as it undermines the trust model that relies on the bootloader to establish a secure execution environment. The impact extends beyond individual device compromise to potentially affect entire device fleets if the vulnerable bootloader versions are widely distributed across different manufacturers and device models.
Mitigation strategies for this vulnerability primarily focus on immediate device updates and firmware patches provided by device manufacturers and Qualcomm. However, due to the nature of the vulnerability, the most effective long-term solution involves complete device replacement or reflashing with secure firmware versions that address the bootloader implementation flaw. Organizations and users should implement strict application vetting processes to prevent installation of potentially malicious applications that could exploit this vulnerability. The vulnerability highlights the importance of secure boot processes and the need for robust hardware-level security measures. Security professionals should monitor for patches and updates from Qualcomm and device manufacturers, as well as implement device monitoring solutions that can detect unauthorized bootloader modifications. This vulnerability also emphasizes the critical need for supply chain security and the importance of hardware-level security verification in mobile device architectures, as it demonstrates how weaknesses in foundational components can lead to complete system compromise.