CVE-2022-20045 in MT8167
Summary
by MITRE • 02/10/2022
In Bluetooth, there is a possible service crash due to a use after free. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS06126820; Issue ID: ALPS06126820.
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Analysis
by VulDB Data Team • 02/14/2022
This vulnerability resides within the Bluetooth subsystem of Android devices and represents a critical use after free condition that can result in arbitrary code execution and local privilege escalation. The flaw occurs when the Bluetooth service processes certain malformed or crafted data structures, leading to memory management errors where freed memory locations are accessed after being deallocated. This particular vulnerability is classified as a use after free error under CWE-416, which occurs when a program continues to reference memory after it has been freed, creating potential for memory corruption and exploitation. The vulnerability affects the Bluetooth service daemon and can be triggered without requiring any user interaction, making it particularly dangerous as it can be exploited remotely or through local attack vectors.
The technical implementation of this vulnerability involves the Bluetooth service's handling of specific packet structures or service discovery protocol messages. When processing these malformed inputs, the service allocates memory for Bluetooth service records or connection management structures, which are then freed during normal operation or error handling. However, subsequent code paths attempt to access these previously freed memory locations, causing undefined behavior that can be leveraged by an attacker. The exploitation process typically involves crafting specific Bluetooth packets or service advertisements that trigger the memory corruption, which can then be used to execute arbitrary code with elevated privileges. This represents a classic privilege escalation vector where an attacker can leverage the Bluetooth service's elevated permissions to gain root access to the device.
The operational impact of this vulnerability extends beyond simple service disruption to represent a complete compromise of device security. Since no user interaction is required for exploitation, attackers can leverage this vulnerability through various attack vectors including unauthorized Bluetooth connections, malicious device pairing attempts, or even through compromised Bluetooth accessories. The local escalation of privilege means that an attacker who gains access to the device through other means can use this vulnerability to elevate their privileges to the highest system level, effectively taking complete control of the device. This vulnerability can be particularly concerning in enterprise environments where Bluetooth-enabled devices are common, as it could allow attackers to compromise multiple devices without requiring physical access or user interaction. The vulnerability affects Android versions prior to specific security patches, and the patch ID ALPS06126820 indicates this was addressed in a system-level update that corrected the memory management error in the Bluetooth service implementation.
Mitigation strategies for this vulnerability focus on immediate patch deployment and system hardening measures. Organizations should prioritize deploying the security update associated with patch ID ALPS06126820 as soon as possible to address the memory management error in the Bluetooth service. System administrators should also consider implementing Bluetooth service restrictions where possible, disabling unnecessary Bluetooth functionality, and monitoring for anomalous Bluetooth activity that could indicate exploitation attempts. Network security controls should include Bluetooth traffic inspection and filtering to prevent malicious Bluetooth packets from reaching vulnerable systems. The vulnerability's classification under the ATT&CK framework would fall under privilege escalation techniques, specifically using service execution or exploitation of system services. Additionally, implementing proper input validation and memory management practices in Bluetooth service implementations can help prevent similar issues. Organizations should also conduct regular security assessments of their Bluetooth-enabled devices and maintain updated threat intelligence to identify potential exploitation attempts targeting this or similar vulnerabilities.