CVE-2021-0633 in MT6580
Summary
by MITRE • 10/25/2021
In display driver, there is a possible out of bounds write due to an incorrect bounds check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS05585423; Issue ID: ALPS05585423.
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Analysis
by VulDB Data Team • 10/30/2021
This vulnerability exists within the display driver component of a mobile operating system and represents a critical out-of-bounds write flaw that can be exploited for local privilege escalation. The issue stems from an incorrect bounds check implementation that fails to properly validate array indices or memory access boundaries before writing data to memory locations. The vulnerability is classified as a memory corruption flaw that allows an attacker to write data beyond the allocated memory buffer, potentially overwriting adjacent memory regions with malicious content.
The technical implementation of this vulnerability demonstrates a classic buffer overflow condition where the display driver fails to validate input parameters or coordinate values passed to graphics rendering functions. When the driver processes display-related operations such as drawing operations, window management, or graphics transformations, it performs insufficient boundary validation before writing to memory arrays. This flaw is particularly dangerous because it operates at the kernel level where display drivers typically execute with high privileges, creating a direct path for privilege escalation from user-level processes to system-level execution.
From an operational perspective, this vulnerability enables local privilege escalation without requiring user interaction, making it particularly concerning for mobile devices where users may not be aware of the underlying system security mechanisms. The exploitation process does not require any user engagement, meaning that an attacker can leverage this flaw through malicious applications or system components that have already gained access to the device. The patch ID ALPS05585423 indicates this was addressed within the Android Linux kernel subsystem, specifically targeting the display driver component. The vulnerability allows an attacker with minimal privileges to execute code with system-level privileges, potentially enabling complete system compromise.
The security implications extend beyond simple privilege escalation as this flaw can be leveraged to bypass various security mechanisms including kernel address space layout randomization and other exploit mitigations. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a specific implementation weakness in memory bounds checking. From an attack framework perspective, this vulnerability maps to the privilege escalation category in the MITRE ATT&CK framework, specifically targeting the 'Privilege Escalation' tactic and 'Local Privilege Escalation' technique. The flaw demonstrates poor input validation practices that are commonly exploited in mobile operating systems where kernel modules interact with user-space applications through various system interfaces.
The remediation approach for this vulnerability involves implementing proper bounds checking mechanisms within the display driver code, ensuring that all memory access operations validate array indices against allocated buffer boundaries before writing data. Security researchers should focus on reviewing all kernel-level graphics drivers for similar bounds checking issues, as this type of vulnerability often indicates broader code quality problems in system components. Organizations should prioritize applying the patch ALPS05585423 and conducting comprehensive security audits of kernel modules to identify potential similar vulnerabilities that could be exploited for privilege escalation attacks. The vulnerability serves as a reminder of the critical importance of memory safety in kernel-level code and the need for rigorous code review processes to prevent such flaws from being introduced into production systems.