CVE-2022-20027 in MT8167
Summary
by MITRE • 02/10/2022
In Bluetooth, 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. Patch ID: ALPS06126826; Issue ID: ALPS06126826.
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Analysis
by VulDB Data Team • 02/14/2022
This vulnerability exists within the Bluetooth subsystem of Android devices and represents a critical out-of-bounds write flaw that can be exploited for local privilege escalation. The issue stems from a missing bounds check in the Bluetooth implementation where an attacker can manipulate input data to trigger memory corruption. The vulnerability is classified as a buffer overflow condition that occurs when the system fails to validate array indices or memory boundaries before writing data. This type of flaw falls under CWE-787: "Out-of-bounds Write" which is a well-documented weakness in software security practices. The vulnerability affects Android versions prior to 2022 and is particularly concerning because it requires no user interaction for exploitation, making it a silent threat that can be triggered through normal Bluetooth operations.
The technical implementation of this vulnerability involves the Bluetooth stack processing incoming packets or data structures without proper validation of buffer sizes or array limits. When malicious data is received through Bluetooth connections, the system attempts to write data beyond the allocated memory boundaries, potentially overwriting adjacent memory regions including critical system structures or privilege control mechanisms. This type of memory corruption can result in arbitrary code execution or privilege escalation, allowing an attacker to gain elevated system privileges. The flaw operates at the kernel level within the Bluetooth driver components, making it particularly dangerous as it can bypass user-space protections and directly impact system integrity. According to ATT&CK framework, this vulnerability maps to T1068: "Local Privilege Escalation" and T1059: "Command and Scripting Interpreter" as exploitation could enable further attack vectors.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides a persistent foothold within the device that can be leveraged for more sophisticated attacks. Once an attacker achieves local privilege escalation, they can access sensitive system data, modify system files, or establish persistent backdoors. The lack of user interaction requirement makes this vulnerability particularly dangerous as it can be exploited silently in the background while the device is in normal operation. The patch ID ALPS06126826 indicates this was addressed in the Android Linux kernel and Android system components, requiring device manufacturers to update their firmware implementations. Security researchers have noted that this type of vulnerability is often discovered through automated fuzzing of kernel components and can remain undetected for extended periods due to its silent nature and lack of user-facing symptoms.
Mitigation strategies for this vulnerability focus on immediate patch deployment and system hardening measures. Organizations should prioritize updating all affected Android devices to the latest security patches available through official channels, as the patch addresses the root cause by implementing proper bounds checking mechanisms. Network administrators should monitor for any unauthorized Bluetooth connections and implement Bluetooth access controls to limit exposure. The vulnerability demonstrates the importance of proper input validation in kernel-level code and emphasizes the need for thorough security testing of system components. Additionally, implementing memory protection mechanisms such as stack canaries, address space layout randomization, and control flow integrity checks can provide additional defense in depth. The vulnerability also highlights the necessity of maintaining up-to-date security patches and the importance of vulnerability management programs that can quickly identify and remediate similar issues across enterprise device fleets.