CVE-2017-7149 in OS X
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13 Supplemental Update is affected. The issue involves the "StorageKit" component. It allows attackers to discover passwords for APFS encrypted volumes by reading Disk Utility hints, because the stored hint value was accidentally set to the password itself, not the entered hint value.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/15/2021
The vulnerability identified as CVE-2017-7149 represents a critical security flaw within Apple's macOS operating system affecting versions prior to 10.13 Supplemental Update. This issue resides within the StorageKit component, which serves as a foundational element for managing storage devices and encryption features on Apple platforms. The flaw specifically impacts APFS (Apple File System) encrypted volumes, which have become the standard encryption mechanism for modern macOS installations. The vulnerability stems from a design oversight where the system incorrectly stored the actual password value in the hint field rather than the user-provided hint text, creating an unintended information disclosure mechanism.
The technical nature of this vulnerability aligns with CWE-200, which addresses improper exposure of sensitive information, and demonstrates how seemingly minor implementation errors can create significant security risks. When users create hints for their encrypted APFS volumes through Disk Utility, the system should store only the hint text provided by the user. However, due to the flaw, the system inadvertently stored the complete password value in the hint field, effectively making the password accessible to anyone who could read the Disk Utility hints. This error occurred at the storage layer where the system should have validated and properly sanitized the hint input before storing it, but instead allowed the raw password value to be persisted in a location where it could be retrieved through normal system operations.
The operational impact of this vulnerability extends beyond simple password exposure, as it fundamentally undermines the security assumptions of APFS encryption. An attacker with access to the affected system could potentially extract the password for encrypted volumes by simply reading the Disk Utility hints, eliminating the need for complex cryptographic attacks or brute force attempts. This vulnerability particularly affects users who rely on hints for their encrypted volumes, as it creates a backdoor that bypasses the intended security controls. The risk is compounded by the fact that these hints are stored in a location that may be accessible through various attack vectors including physical access, remote exploitation, or privilege escalation scenarios. The vulnerability also has implications for compliance with security standards such as those outlined in the NIST Special Publication 800-111, which emphasizes the importance of protecting cryptographic keys and passwords through proper storage mechanisms.
Mitigation strategies for CVE-2017-7149 primarily focus on upgrading to macOS 10.13 Supplemental Update or later versions where Apple has corrected the StorageKit implementation. Organizations should conduct immediate assessments of their macOS environments to identify systems running vulnerable versions and prioritize patching efforts. Additionally, users should be educated about the risks of using hints for encrypted volumes, as the vulnerability demonstrates how even seemingly benign features can create security weaknesses. Security teams should monitor for potential exploitation attempts and consider implementing additional access controls to limit who can read system hint files. The vulnerability also highlights the importance of proper input validation and secure coding practices, particularly in components that handle sensitive information. From an ATT&CK framework perspective, this vulnerability maps to techniques involving credential access and privilege escalation, as attackers can leverage the exposed passwords to gain deeper system access. Organizations should also review their overall encryption strategies and consider implementing additional layers of security beyond simple hint systems to protect against similar implementation flaws.