CVE-2016-8423 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-31399736. References: QC-CR#1000546.
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Analysis
by VulDB Data Team • 10/27/2022
The vulnerability identified as CVE-2016-8423 represents a critical elevation of privilege flaw within the Qualcomm bootloader component that serves as a foundational element in Android device security architecture. This vulnerability exists at the lowest level of the system where the bootloader initializes hardware components and loads the operating system kernel, making it a prime target for attackers seeking persistent system compromise. The issue specifically affects devices that utilize Qualcomm chipsets, where the bootloader implementation contains a flaw that allows a locally installed malicious application to escalate its privileges and execute code with kernel-level permissions. Such a vulnerability fundamentally undermines the security model of Android devices by providing a pathway for malicious software to bypass the normal privilege separation mechanisms that protect the kernel from unauthorized access.
The technical nature of this vulnerability stems from improper input validation or memory handling within the bootloader code that fails to properly authenticate or validate execution contexts. When a malicious application attempts to exploit this flaw, it can leverage the bootloader's insufficient protections to gain unauthorized access to kernel execution space, effectively allowing arbitrary code execution with the highest possible privileges. This type of vulnerability falls under CWE-248, which addresses "Uncaught Exception" conditions where an exception is not properly handled, potentially leading to privilege escalation. The attack vector requires local execution privileges, meaning the malicious application must first be installed on the device, but once executed, it can leverage this bootloader weakness to achieve persistent kernel-level access that traditional security measures cannot prevent.
The operational impact of CVE-2016-8423 is severe and potentially permanent, as the vulnerability allows for complete system compromise without requiring external network access or complex exploitation techniques. A successful attack can result in the complete takeover of the device's functionality, enabling the malicious application to modify system files, install persistent backdoors, access encrypted data, and potentially disable security features entirely. This level of compromise aligns with the ATT&CK framework's privilege escalation techniques, specifically targeting the 'Boot or Logon Initialization Scripts' and 'Exploitation for Privilege Escalation' tactics. The requirement for device reflashing to remediate this vulnerability indicates that the compromise is not merely temporary but fundamentally alters the device's boot process and security state, making it a particularly dangerous flaw that affects the device's core security posture.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term prevention measures. Device manufacturers should implement firmware updates that correct the bootloader implementation flaws, though the severity of the vulnerability means that users may need to perform complete device re-flashing to restore proper security. Security researchers and organizations should monitor for exploitation attempts and implement device monitoring solutions that can detect anomalous boot processes or unauthorized modifications to system components. The vulnerability also highlights the importance of secure boot processes and the need for robust hardware-level security implementations that prevent local applications from exploiting low-level system components. Additionally, organizations should consider implementing network-based monitoring to detect potential exploitation attempts and maintain comprehensive backup and recovery procedures that account for the possibility of complete device compromise requiring full system restoration.