CVE-2022-20109 in MT6580
Summary
by MITRE • 05/04/2022
In ion, there is a possible use after free due to improper update of reference count. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS06399915; Issue ID: ALPS06399915.
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Analysis
by VulDB Data Team • 05/07/2022
The vulnerability identified as CVE-2022-20109 resides within the ion memory management subsystem of Android devices, representing a critical use after free condition that can be exploited for local privilege escalation. This flaw manifests in the improper handling of reference count updates within the ion driver, which is responsible for managing shared memory allocations between different processes and kernel components. The ion subsystem serves as a core memory management interface in Android's memory architecture, facilitating efficient memory sharing between applications and system services while maintaining proper reference counting to prevent premature deallocation of memory regions.
The technical root cause of this vulnerability stems from a race condition or logic error in the reference counting mechanism that governs ion memory buffers. When memory objects are allocated through the ion subsystem, they maintain a reference count that tracks how many processes or components are currently utilizing that memory region. The flaw occurs when this reference count is not properly updated during certain memory management operations, leading to a scenario where a memory buffer can be freed while still being referenced by another component. This improper reference count management creates a use after free condition where subsequent operations on the freed memory can result in arbitrary code execution or privilege escalation.
The operational impact of CVE-2022-20109 is particularly severe as it enables local privilege escalation without requiring any user interaction or additional execution privileges. This means that any process running with standard user privileges can potentially exploit this vulnerability to gain elevated system-level access. The lack of user interaction requirements makes this vulnerability especially dangerous as it can be exploited automatically by malicious applications or processes without any human intervention. The vulnerability affects devices running Android versions where the patched ion driver is present, making it a widespread concern across numerous Android devices and versions.
The exploitation of this vulnerability aligns with ATT&CK technique T1068, which involves the exploitation of legitimate credentials and system access to gain elevated privileges. This particular flaw demonstrates how memory corruption vulnerabilities in kernel-level subsystems can be leveraged for privilege escalation, as the reference counting error creates a predictable memory access pattern that can be manipulated by malicious code. The vulnerability also relates to CWE-416, which describes the use of freed memory condition, and CWE-787, which covers out-of-bounds write operations that can occur when memory management structures are corrupted. The patch ID ALPS06399915 indicates this was addressed through a specific kernel update that properly handles the reference counting operations within the ion subsystem, ensuring that memory objects remain valid until all references are properly released.
Mitigation strategies for CVE-2022-20109 primarily involve applying the vendor-provided security patches that correct the reference counting logic within the ion memory management driver. System administrators and device manufacturers should prioritize updating all affected Android devices to versions that include the ALPS06399915 patch. Additionally, organizations should implement monitoring for suspicious memory management operations and consider deploying runtime protection mechanisms that can detect anomalous reference counting behaviors. The vulnerability underscores the importance of proper memory management practices in kernel-level code and highlights the critical need for thorough testing of memory management operations to prevent similar use after free conditions from occurring in other subsystems.