CVE-2017-0502 in Android
Summary
by MITRE
An elevation of privilege vulnerability in MediaTek components, including the M4U driver, sound driver, touchscreen driver, GPU driver, and Command Queue driver, 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-28430164. References: M-ALPS02710027.
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Analysis
by VulDB Data Team • 09/05/2020
The vulnerability identified as CVE-2017-0502 represents a critical elevation of privilege flaw affecting MediaTek-based Android devices through multiple kernel drivers including M4U, sound, touchscreen, GPU, and Command Queue drivers. This weakness allows a locally malicious application to escalate its privileges and execute arbitrary code within the kernel context, effectively bypassing Android's security model and potentially compromising the entire device. The vulnerability stems from improper input validation and privilege checking mechanisms within MediaTek's proprietary driver implementations, creating a persistent backdoor for attackers to gain root-level access to the operating system.
From a technical perspective, this vulnerability manifests as a privilege escalation in the kernel space through MediaTek's hardware abstraction layer components that manage critical device functionalities. The affected drivers operate at the highest privilege level within the Android architecture, making any flaw in their implementation particularly dangerous. The M4U driver, which handles memory management unit operations, and the GPU driver, which manages graphics processing, are especially vulnerable due to their direct hardware interaction and lack of proper access controls. This flaw aligns with CWE-269: "Improper Privilege Management" and CWE-276: "Incorrect Default Permissions", as the drivers fail to properly enforce access controls and maintain appropriate privilege boundaries.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it enables persistent device compromise that can only be resolved through complete system reinstallation. A malicious application with local access can leverage this vulnerability to gain root privileges, allowing it to modify system files, install persistent backdoors, and completely subvert the device's security framework. The attack surface is particularly concerning because these drivers are essential for normal device operation, meaning the vulnerability cannot be easily patched without affecting core functionality. This makes the device susceptible to permanent compromise where attackers can maintain control even after device reboots, effectively rendering the device unusable without complete factory reset or hardware replacement.
Security professionals should recognize this vulnerability as a prime example of supply chain risk in mobile devices, where third-party component vendors create security flaws that affect millions of end users. The ATT&CK framework categorizes this as privilege escalation through kernel exploits, specifically targeting the 'Exploitation for Privilege Escalation' technique. Mitigation strategies must include immediate patching of affected MediaTek components, implementation of runtime integrity checks, and enhanced application sandboxing to prevent local privilege escalation attacks. Organizations should also consider device hardening measures such as kernel address space layout randomization, secure boot implementations, and regular security audits of vendor-provided drivers to prevent similar vulnerabilities from affecting their mobile device fleets. The vulnerability demonstrates the critical importance of proper driver security implementation and the need for comprehensive security testing of all kernel-level components in mobile operating systems.