CVE-2019-8522 in macOS
Summary
by MITRE
A logic issue was addressed with improved state management. This issue is fixed in macOS Mojave 10.14.4. An encrypted volume may be unmounted and remounted by a different user without prompting for the password.
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Analysis
by VulDB Data Team • 05/21/2020
The vulnerability described in CVE-2019-8522 represents a significant security flaw in macOS Mojave's handling of encrypted volumes and their access controls. This logic issue stems from inadequate state management within the operating system's volume handling mechanisms, specifically affecting the security boundaries between different user sessions. The flaw allows for unauthorized access to encrypted data through a process that should require explicit authentication, undermining the fundamental security model that protects user data through cryptographic encryption and access control.
The technical nature of this vulnerability lies in the improper state management of encrypted volumes during the unmounting and remounting processes. When an encrypted volume is unmounted by one user account, the system fails to properly enforce access controls that would normally require re-authentication when the same volume is remounted by a different user. This represents a violation of the principle of least privilege and demonstrates a failure in the operating system's access control mechanisms. The vulnerability specifically affects macOS Mojave version 10.14.3 and earlier, where the system's state management does not adequately track or enforce the security context of volume access across user sessions.
The operational impact of this vulnerability extends beyond simple unauthorized data access to represent a broader compromise of system integrity and user privacy. An attacker who gains access to a system with a mounted encrypted volume could potentially escalate privileges by simply unmounting the volume and remounting it under their own user account without providing the original password. This creates a scenario where sensitive data that should remain protected by cryptographic means becomes accessible to any user with sufficient system access, potentially exposing personal information, business data, or confidential communications stored on the encrypted volumes. The vulnerability is particularly concerning in multi-user environments where different users may share the same physical system or where system administrators have access to multiple user accounts.
The security implications of this vulnerability align with several established frameworks and classifications including CWE-284, which addresses improper access control, and can be mapped to ATT&CK technique T1003.001 for credential access through os credential storage. The vulnerability represents a failure in the operating system's privilege separation mechanisms and demonstrates how inadequate state management can create security boundaries that are easily traversed. Organizations using affected versions of macOS should immediately implement the patch released in macOS Mojave 10.14.4, which addresses the root cause by improving the state management of encrypted volume access controls. Additionally, system administrators should review existing access control policies and consider implementing additional security measures such as mandatory access controls, enhanced monitoring of volume mounting operations, and regular security audits to detect potential exploitation attempts. The remediation process should include verifying that all systems have been updated to the patched version and confirming that the improved state management mechanisms are properly enforcing access controls for encrypted volumes.