CVE-2021-0668 in MT6873
Summary
by MITRE • 11/18/2021
In apusys, there is a possible memory corruption due to incorrect error handling. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS05670521; Issue ID: ALPS05670521.
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Analysis
by VulDB Data Team • 11/22/2021
The vulnerability identified as CVE-2021-0668 affects the apusys component within Android systems, representing a critical memory corruption flaw that stems from inadequate error handling mechanisms. This issue resides within the system's kernel or low-level drivers where memory management operations are performed, creating a pathway for malicious actors to exploit fundamental system protections. The vulnerability specifically manifests when the system processes certain memory allocation or deallocation operations, failing to properly validate or handle error conditions that should trigger protective mechanisms. The flaw operates at a foundational level where the system's memory management subsystem does not adequately protect against corrupted memory states that could be manipulated by unauthorized processes.
The technical implementation of this vulnerability demonstrates how improper error handling in kernel space can lead to memory corruption that bypasses standard security boundaries. When the apusys component encounters exceptional conditions during memory operations, the system fails to implement proper safeguards that would normally prevent memory from being overwritten or corrupted in ways that could be exploited. This type of vulnerability typically involves buffer overflows, use-after-free conditions, or other memory management errors where the system's error recovery mechanisms are insufficient to prevent malicious exploitation. The flaw aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read conditions that can result from improper memory handling. The vulnerability's classification as a local privilege escalation means that an attacker with minimal system access could potentially leverage this flaw to gain elevated privileges and execute code with system-level permissions.
The operational impact of CVE-2021-0668 extends beyond simple memory corruption, as it enables unauthorized users to achieve system-level privileges without requiring user interaction, making it particularly dangerous in environments where multiple users or processes share the same system. The exploitation process requires only system execution privileges, meaning that even users with standard permissions could potentially leverage this vulnerability to gain root access. This characteristic places the vulnerability in the ATT&CK framework under privilege escalation techniques, specifically targeting the execution of malicious code with elevated privileges. The lack of user interaction requirements significantly reduces the attack surface and makes this vulnerability particularly concerning for mobile devices, IoT systems, and embedded platforms where users may not have full control over system processes. The patch ID ALPS05670521 indicates that this vulnerability was addressed through a specific system update that modified the error handling mechanisms within the apusys component to properly validate memory operations and prevent the corruption states that could lead to privilege escalation.
Mitigation strategies for CVE-2021-0668 should prioritize immediate system updates and patches provided by device manufacturers, as these address the root cause through proper error handling implementation. Organizations should implement comprehensive vulnerability management processes that include regular system monitoring and verification of patch status across all affected devices. The remediation efforts should focus on ensuring that memory management operations within the apusys component properly validate all error conditions and implement appropriate safeguards against memory corruption. Security teams should also consider implementing runtime protections and monitoring mechanisms that can detect anomalous memory behavior patterns that might indicate exploitation attempts. Additional defensive measures include restricting system access privileges, implementing secure coding practices for kernel-level components, and maintaining detailed system logs that can help identify potential exploitation attempts. The vulnerability highlights the importance of robust error handling in system-level code and demonstrates how seemingly minor implementation flaws can create significant security risks that undermine system integrity and user data protection.