CVE-2022-21775 in MT6761
Summary
by MITRE • 07/06/2022
In sched driver, there is a possible use after free due to improper locking. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS06479032; Issue ID: ALPS06479032.
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Analysis
by VulDB Data Team • 07/19/2022
The vulnerability identified as CVE-2022-21775 resides within the scheduling driver component of a Linux kernel implementation, specifically affecting Android-based systems where ALPS06479032 serves as the patch identifier. This flaw represents a critical security weakness that stems from inadequate locking mechanisms during scheduler operations, creating a scenario where memory management becomes compromised. The scheduling driver is responsible for managing process execution and resource allocation within the operating system, making it a prime target for privilege escalation attacks.
The technical root cause of this vulnerability manifests as a use-after-free condition that occurs when the scheduler attempts to access memory that has already been freed due to insufficient synchronization primitives. This improper locking allows concurrent threads or processes to access the same memory location at inappropriate times, leading to memory corruption that can be exploited by malicious code. The flaw specifically impacts the kernel's scheduler module which manages process scheduling and resource allocation, creating a dangerous state where freed memory can be reallocated and accessed by unauthorized code paths. This type of vulnerability falls under the CWE-416 category of Use After Free, which is classified as a critical weakness in memory management.
The operational impact of this vulnerability is severe as it enables local privilege escalation without requiring user interaction, meaning any process running with standard user privileges could potentially exploit this weakness to gain system-level execution rights. This represents a significant threat to system integrity since the attacker does not need to trick users into performing specific actions, the vulnerability can be triggered automatically. The exploitation process would involve carefully timing the execution of scheduler operations to force the use-after-free condition, potentially allowing an attacker to execute arbitrary code with kernel privileges. This capability directly violates the principle of least privilege and undermines the fundamental security model of the operating system.
Mitigation strategies for CVE-2022-21775 should focus on implementing proper locking mechanisms within the scheduler driver to prevent concurrent access to shared memory regions. The patch ALPS06479032 addresses this issue by introducing appropriate synchronization primitives that ensure memory access occurs only when safe. Organizations should prioritize applying this patch immediately, as the vulnerability does not require user interaction for exploitation and represents a high-severity threat. System administrators should also consider implementing additional monitoring for unusual scheduler behavior and memory access patterns that could indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and specifically relates to T1068 which involves exploiting legitimate credentials or system processes to gain elevated privileges, making it a critical target for defensive measures and incident response protocols.