CVE-2022-20122 in Android
Summary
by MITRE • 08/24/2022
The PowerVR GPU driver allows unprivileged apps to allocated pinned memory, unpin it (which makes it available to be freed), and continue using the page in GPU calls. No privileges required and this results in kernel memory corruption.Product: AndroidVersions: Android SoCAndroid ID: A-232441339
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Analysis
by VulDB Data Team • 09/25/2022
The vulnerability identified as CVE-2022-20122 resides within the PowerVR GPU driver component of Android SoC implementations, representing a critical memory management flaw that undermines kernel security boundaries. This issue specifically affects the handling of pinned memory operations within the graphics processing unit driver, creating a persistent security weakness that enables arbitrary code execution through improper memory lifecycle management. The vulnerability manifests when unprivileged applications can manipulate pinned memory pages in ways that should be restricted to privileged kernel components, fundamentally compromising the integrity of the operating system's memory management subsystem. This flaw directly violates fundamental security principles by allowing user-space processes to manipulate kernel memory structures through legitimate GPU operations.
The technical implementation of this vulnerability stems from inadequate validation of memory pinning operations within the PowerVR driver's kernel module. When applications allocate pinned memory for GPU processing, the driver should maintain strict control over memory page lifecycle management to prevent unauthorized access or manipulation. However, the flaw allows applications to unpin memory pages, making them available for kernel memory management operations including potential freeing, while simultaneously continuing to reference those same pages in subsequent GPU commands. This creates a race condition and memory inconsistency where the kernel believes the memory is available for reuse or deallocation, yet user-space applications continue to utilize the same memory addresses for GPU operations. The vulnerability specifically affects the memory management subsystem's ability to track page usage and availability, creating a persistent state where kernel memory can be corrupted through legitimate GPU operations.
The operational impact of CVE-2022-20122 extends far beyond simple memory corruption, as it enables complete privilege escalation and arbitrary code execution within the kernel context. Attackers can leverage this vulnerability to gain root access to the Android device, effectively bypassing all user-space security controls and gaining unrestricted access to system resources, user data, and device functionality. The flaw's exploitation requires no special privileges or user interaction, making it particularly dangerous as it can be triggered by any installed application without requiring user consent or elevated permissions. This vulnerability represents a classic case of kernel memory corruption that can be exploited through the use of the Common Weakness Enumeration (CWE-119) category, specifically addressing weaknesses in memory safety and improper handling of memory allocation lifecycles. The attack surface includes all Android devices utilizing PowerVR GPU drivers, affecting a wide range of mobile devices, tablets, and embedded systems that depend on this graphics processing architecture.
Mitigation strategies for CVE-2022-20122 must address both immediate defensive measures and long-term architectural improvements to prevent similar vulnerabilities. Device manufacturers should implement immediate patches to the PowerVR GPU driver that enforce stricter memory pinning controls and prevent unprivileged applications from manipulating kernel memory pages in this manner. The solution requires implementing proper memory lifecycle management that prevents the unpinning operation from making pages available for kernel freeing while maintaining active GPU references. Additionally, system administrators should consider implementing runtime monitoring to detect suspicious memory operations and establish proper privilege separation between user-space applications and kernel memory management components. This vulnerability aligns with the ATT&CK framework's privilege escalation techniques, specifically targeting the T1068 - Exploitation for Privilege Escalation tactic, and requires defensive measures that include kernel memory protection mechanisms, enhanced driver validation, and proper access controls to prevent unauthorized memory manipulation operations. The remediation should also include comprehensive testing of memory management operations and implementation of proper memory validation checks to prevent similar issues in future driver implementations.