CVE-2022-20572 in Android
Summary
by MITRE • 12/16/2022
In verity_target of dm-verity-target.c, there is a possible way to modify read-only files due to a missing permission check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-234475629References: Upstream kernel
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 04/22/2026
The vulnerability identified as CVE-2022-20572 resides within the dm-verity-target component of the Android kernel, specifically in the verity_target implementation within the dm-verity-target.c source file. This flaw represents a critical security weakness that undermines the integrity protection mechanisms designed to prevent unauthorized modifications to read-only filesystems. The dm-verity system serves as a cryptographic verification layer that ensures data integrity by detecting any modifications to files after they have been installed on the device. When this protection is bypassed, it creates a fundamental breach in the system's security architecture that can be exploited by malicious actors.
The technical root cause of this vulnerability stems from a missing permission check within the verity_target function that handles read-only file operations. This absence allows unauthorized code execution to bypass the normal access controls that should prevent modifications to protected filesystem components. The flaw specifically affects the verification process that occurs when the kernel attempts to validate the integrity of files within the dm-verity protected volumes. According to the Android Security Team's assessment, this vulnerability enables local privilege escalation without requiring user interaction, making it particularly dangerous as it can be exploited automatically by malicious applications already running on the device.
The operational impact of CVE-2022-20572 extends beyond simple file modification capabilities as it provides a pathway for attackers to escalate their privileges from regular user level to system level execution. This privilege escalation occurs through the manipulation of read-only filesystems that are typically protected by the dm-verity mechanism. The vulnerability requires system execution privileges to be exploited, which means that an attacker must already have some level of access to the system to leverage this weakness. However, once exploited, the attack can result in complete system compromise as the attacker gains the ability to modify critical system files and potentially escalate to root privileges. This vulnerability aligns with CWE-284, which describes improper access control issues, and represents a clear violation of the principle of least privilege that should govern all system operations.
The exploitation of this vulnerability demonstrates the critical importance of proper permission checking in kernel-level code, particularly in security-sensitive components like dm-verity. Attackers can leverage this flaw to modify system binaries, install malicious code, or otherwise compromise the integrity of the Android system. The fact that no user interaction is required for exploitation makes this vulnerability particularly concerning as it can be triggered automatically when the affected kernel components are accessed. Mitigation strategies should include immediate patching of the kernel to address the missing permission check in the dm-verity-target.c file, along with comprehensive monitoring for any unauthorized modifications to system files that might indicate exploitation attempts. Organizations should also implement additional security controls such as runtime integrity monitoring and privilege separation mechanisms to reduce the overall risk of this type of vulnerability being successfully exploited. The vulnerability serves as a reminder of the critical need for thorough code review processes and security testing in kernel development, particularly for components that handle cryptographic verification and access control functions.