CVE-2022-42534 in Android
Summary
by MITRE • 12/16/2022
In trusty_ffa_mem_reclaim of shared-mem-smcall.c, there is a possible privilege escalation due to improper input validation. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-237838301References: N/A
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Analysis
by VulDB Data Team • 04/17/2025
The vulnerability identified as CVE-2022-42534 resides within the Android kernel's trusty firmware implementation, specifically in the trusty_ffa_mem_reclaim function located in shared-mem-smcall.c. This flaw represents a critical privilege escalation vulnerability that allows local attackers to elevate their privileges without requiring additional execution privileges or user interaction. The vulnerability stems from inadequate input validation mechanisms within the memory reclaim functionality of the trusted firmware, which is designed to manage shared memory operations between different security domains within the Android ecosystem. The trusty firmware serves as a critical security component that isolates sensitive operations and maintains the integrity of the device's security boundaries.
The technical flaw manifests through improper validation of memory management parameters during the FFA (Flexible Firmware API) memory reclaim process. When the trusty_ffa_mem_reclaim function processes memory reclaim requests, it fails to adequately verify the legitimacy of input parameters that define memory regions and access permissions. This validation gap enables an attacker to manipulate memory management structures in ways that were not intended by the firmware design. The vulnerability operates at the kernel level within the trusted execution environment, where memory operations are expected to maintain strict access controls and prevent unauthorized memory manipulation. This weakness creates a pathway for privilege escalation by allowing malicious code to bypass normal access control mechanisms that should prevent unauthorized memory operations.
The operational impact of this vulnerability extends beyond simple privilege escalation as it fundamentally compromises the security model of the Android kernel's trusted firmware. An attacker with local access to the device can exploit this vulnerability to gain elevated privileges that would normally be restricted to the kernel or trusted firmware components. The attack does not require user interaction or additional privileges, making it particularly dangerous as it can be exploited automatically. The vulnerability affects the Android kernel's ability to maintain proper memory isolation between different security contexts, potentially allowing an attacker to access sensitive data, modify system memory, or execute arbitrary code with kernel-level privileges. This compromise undermines the core security principles of the Android platform's hardware security module.
Mitigation strategies for CVE-2022-42534 should focus on implementing robust input validation mechanisms within the trusty firmware memory management functions. The fix requires comprehensive parameter validation that ensures all memory reclaim operations adhere to strict access control policies and memory boundary checks. Organizations should prioritize updating to patched kernel versions that address the improper input validation in the trusty_ffa_mem_reclaim function. Additionally, security teams should implement monitoring for anomalous memory management operations that could indicate exploitation attempts. The vulnerability aligns with CWE-20 Improper Input Validation, which is a fundamental weakness in software design that allows malicious input to cause unexpected behavior. This type of vulnerability is categorized under ATT&CK technique T1068, which involves exploiting legitimate credentials or system privileges to gain unauthorized access. System administrators should also consider implementing additional runtime protections and memory integrity checks to detect and prevent exploitation attempts targeting this specific memory management flaw.