CVE-2017-13909 in macOS
Summary
by MITRE • 12/23/2021
An issue existed in the storage of sensitive tokens. This issue was addressed by placing the tokens in Keychain. This issue is fixed in macOS High Sierra 10.13. A local attacker may gain access to iCloud authentication tokens.
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Analysis
by VulDB Data Team • 12/27/2021
The vulnerability identified as CVE-2017-13909 represents a critical security flaw in macOS High Sierra versions prior to 10.13, where sensitive authentication tokens were improperly stored within the system's file system rather than being secured in the dedicated Keychain service. This misconfiguration created a significant attack surface that allowed local adversaries to potentially access iCloud authentication credentials. The issue stems from improper handling of sensitive data storage mechanisms, where tokens that should have been protected using macOS's built-in secure credential management system were instead stored in accessible locations. This flaw directly violates security best practices for credential management and represents a failure in the system's defense-in-depth principles. The vulnerability is categorized under CWE-312, which specifically addresses the exposure of sensitive information through improper data storage, and aligns with ATT&CK technique T1552.001 for Unsecured Credentials. The improper storage of authentication tokens creates a persistent security risk that can be exploited by attackers with local system access, potentially leading to unauthorized access to user iCloud accounts and associated services.
The technical implementation of this vulnerability involved the application's failure to utilize macOS Keychain services for sensitive token storage. Instead of leveraging the secure Keychain API which provides encryption, access controls, and proper credential management, the system stored tokens in plain text or inadequately protected files within the user's home directory or system locations. This approach exposes the tokens to any process running with the same user privileges, effectively eliminating the security boundaries that should protect authentication credentials. The flaw demonstrates a lack of proper input validation and secure coding practices, where sensitive data handling was not properly implemented according to security standards. Attackers could exploit this vulnerability by simply navigating to the token storage locations and extracting the authentication information, which would then allow them to impersonate the user and access iCloud services without requiring additional authentication factors.
The operational impact of this vulnerability extends beyond simple credential theft, as iCloud authentication tokens provide access to a wide range of sensitive user data including documents, photos, contacts, and other personal information stored in Apple's cloud services. Local attackers who successfully extract these tokens can maintain persistent access to user accounts, potentially leading to data exfiltration, identity theft, and further exploitation within the user's cloud environment. The vulnerability also creates a risk for privilege escalation attacks, as attackers may use the stolen tokens to access additional services or systems that trust the compromised iCloud credentials. This issue affects all macOS High Sierra versions prior to 10.13, representing a substantial attack surface across a significant user base. The vulnerability's exploitation does not require network connectivity or complex attack chains, making it particularly dangerous as it can be exploited with minimal resources and technical knowledge.
The remediation for CVE-2017-13909 involved implementing proper secure credential storage using macOS Keychain services, which provides encrypted storage with access controls and proper authentication mechanisms. This fix ensures that sensitive tokens are protected using the system's built-in security infrastructure rather than being stored in accessible file locations. Organizations should ensure that all affected systems are updated to macOS High Sierra 10.13 or later versions to mitigate this vulnerability. Additionally, system administrators should implement monitoring for unauthorized access attempts to credential storage locations and conduct regular security audits to verify proper implementation of secure credential handling. The fix aligns with security frameworks that emphasize the importance of using platform-provided secure storage mechanisms and proper data protection measures. This vulnerability serves as a reminder of the critical importance of secure credential management and the necessity of following established security guidelines for handling sensitive authentication information in operating system implementations.