CVE-2021-0489 in Android
Summary
by MITRE • 06/11/2021
In memory management driver, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android SoCAndroid ID: A-183464866
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Analysis
by VulDB Data Team • 06/14/2021
The vulnerability identified as CVE-2021-0489 resides within the memory management driver component of Android operating systems, specifically affecting Android SoC implementations. This flaw represents a critical security weakness that stems from inadequate input validation mechanisms within the kernel-level memory management subsystem. The issue manifests as a missing bounds check during memory operations, creating a pathway for unauthorized privilege escalation. The vulnerability affects Android versions where the memory management driver is implemented, with the specific Android ID A-183464866 documenting the affected implementations.
The technical flaw constitutes an out-of-bounds write condition that occurs when the memory management driver processes certain memory allocation or deallocation requests. Without proper bounds checking mechanisms, the driver fails to validate memory access boundaries before writing data to memory locations. This allows an attacker to write data beyond the intended memory buffer, potentially overwriting critical kernel data structures or executable code. The vulnerability's classification as a local privilege escalation means that an attacker with minimal privileges can leverage this flaw to gain elevated system-level access. The missing bounds check creates an exploitable condition where malicious input can cause memory corruption that leads to arbitrary code execution in kernel space.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete control over the affected Android device. Since no user interaction is required for exploitation, the vulnerability can be triggered automatically through legitimate system processes or malicious applications. The local nature of the exploit means that attackers do not need network access or additional attack vectors to leverage this weakness. This makes the vulnerability particularly dangerous in environments where untrusted applications can be installed or where the device is compromised through other attack vectors. The exploitability is further enhanced by the fact that the memory management driver operates with high privileges, making any successful exploitation result in complete system compromise.
Mitigation strategies for CVE-2021-0489 should focus on implementing comprehensive bounds checking mechanisms within the memory management driver and applying timely security patches from device manufacturers. Organizations should prioritize updating affected Android implementations to versions that include the necessary fixes for the bounds checking vulnerability. System administrators should monitor for security advisories from Google and device vendors, as the patch implementation typically involves kernel-level modifications that require careful deployment. The vulnerability aligns with CWE-129, which addresses improper validation of array indices, and can be categorized under ATT&CK technique T1068, which covers exploit for privilege escalation. Additional protective measures include implementing kernel address space layout randomization, enabling stack canaries, and employing memory protection mechanisms such as read-only data sections to limit the impact of potential exploitation attempts.