CVE-2018-4179 in macOS
Summary
by MITRE
In macOS High Sierra before 10.13.4, there was an issue with the handling of smartcard PINs. This issue was addressed with additional logic.
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Analysis
by VulDB Data Team • 04/28/2020
The vulnerability identified as CVE-2018-4179 represents a security flaw in macOS High Sierra versions prior to 10.13.4 that specifically affects the handling of smartcard personal identification numbers. This issue falls under the category of credential management and authentication mechanisms within operating system security frameworks. The flaw stems from insufficient validation and processing of smartcard PIN inputs, creating potential attack vectors that could compromise user authentication security. Smartcard-based authentication systems are widely deployed in enterprise environments and government sectors where strong authentication is required, making this vulnerability particularly concerning for organizations relying on such security measures. The vulnerability's impact extends beyond simple credential theft as it could potentially enable unauthorized access to systems protected by smartcard authentication, undermining the security posture of affected organizations. According to CWE classification, this issue relates to CWE-257, which deals with the storage of passwords in a recoverable format, though the specific implementation flaw manifests in the PIN processing rather than storage mechanisms. The vulnerability demonstrates a weakness in the input validation procedures within the macOS smartcard subsystem, where the operating system fails to properly validate or sanitize PIN entries before processing them through the authentication framework.
The technical implementation of this flaw occurs within the macOS security subsystem that handles smartcard communication and authentication protocols. When users attempt to authenticate using smartcards, the system processes PIN entries through a validation mechanism that lacks proper input sanitization and boundary checking. This insufficient logic allows for potential manipulation of the authentication flow, potentially enabling attackers to bypass normal PIN validation procedures or exploit the authentication system in unexpected ways. The vulnerability likely stems from improper handling of edge cases in PIN processing, where the system does not adequately account for malformed inputs or unexpected sequences that could be leveraged to gain unauthorized access. Attackers could potentially exploit this weakness by crafting specific PIN inputs that trigger the flawed validation logic, potentially leading to successful authentication without proper authorization. The implementation flaw exists in the kernel-level or system-level components responsible for smartcard communication protocols, making it particularly dangerous as it operates at a fundamental level of the operating system's security infrastructure. This type of vulnerability aligns with ATT&CK technique T1213 which covers credential access through the exploitation of system vulnerabilities, specifically targeting authentication mechanisms.
The operational impact of CVE-2018-4179 extends significantly across various deployment scenarios where macOS systems are used for smartcard-based authentication. Organizations utilizing smartcards for secure access to networks, databases, and sensitive systems face potential exposure to unauthorized access if they operate affected macOS versions. The vulnerability could enable attackers to gain access to enterprise networks, protected databases, and sensitive information systems that rely on smartcard authentication as part of their security architecture. In government and military environments where smartcard authentication is standard practice, this vulnerability could represent a serious security risk that compromises classified information access controls. The exploitation of this vulnerability would likely require local access or network-based attack vectors that could be leveraged by sophisticated adversaries. System administrators and security teams would need to urgently assess their macOS deployments for affected versions and implement remediation measures to prevent potential exploitation. The vulnerability's impact is particularly severe because it affects the core authentication mechanisms that protect critical infrastructure, making it a high-priority issue for security operations centers and enterprise security teams. Organizations should consider this vulnerability as part of their broader security posture assessment, particularly when evaluating their risk management strategies for authentication systems.
Mitigation strategies for CVE-2018-4179 primarily focus on upgrading affected macOS systems to version 10.13.4 or later, which contains the necessary security patches addressing the smartcard PIN handling issue. System administrators should prioritize patch deployment across all affected macOS systems, particularly those in high-security environments where smartcard authentication is critical. Additional mitigations include implementing network segmentation to limit access to systems that utilize smartcard authentication, monitoring for unusual authentication patterns that could indicate exploitation attempts, and ensuring proper access controls are in place to limit the potential impact of any successful attacks. Organizations should also consider implementing multi-factor authentication mechanisms as additional layers of security beyond smartcard authentication. Security teams should conduct thorough vulnerability assessments to identify all systems running affected macOS versions and establish monitoring procedures to detect potential exploitation attempts. The patch provided by Apple addresses the root cause by implementing additional validation logic that properly handles smartcard PIN inputs and prevents the exploitation pathways that were previously possible. Regular security updates and patch management procedures should be reinforced to prevent similar vulnerabilities from occurring in the future. Organizations may also want to consider alternative authentication methods or additional security controls for environments where the risk of exploitation remains high even after patching. Proper incident response procedures should be established to quickly detect and respond to any potential exploitation attempts targeting this specific vulnerability.