CVE-2023-42891 is a security vulnerability identified in Apple macOS operating systems, specifically affecting versions prior to macOS Sonoma 14.2, Ventura 13.6.3, and Monterey 12.7.2. The root cause is an authentication issue stemming from improper state management within the OS, which allows an application to monitor keystrokes without requiring explicit user permission. This bypass of the standard macOS security model undermines the system’s privacy controls, enabling potentially malicious apps to capture all keyboard input stealthily. Such input may include sensitive information like passwords, personal messages, and confidential business data. The vulnerability was addressed by Apple through improved state management mechanisms in the specified patched versions. Although no public exploits have been reported, the flaw presents a significant risk because it does not require user interaction beyond app installation, and it can be exploited by any app that gains execution privileges on the system. The lack of a CVSS score indicates that the vulnerability is newly disclosed, but the nature of the flaw suggests a high impact on confidentiality and integrity. The vulnerability affects all users running vulnerable macOS versions, including enterprise environments where macOS is used for development, administration, or end-user computing. Attackers exploiting this vulnerability could conduct espionage, credential theft, or data exfiltration without detection. The issue highlights the importance of strict app vetting and permission controls in macOS environments.

For European organizations, the impact of CVE-2023-42891 can be severe, particularly for sectors that rely heavily on macOS devices such as technology firms, creative industries, financial services, and government agencies. Unauthorized keystroke monitoring can lead to the compromise of sensitive credentials, intellectual property, and personal data, potentially resulting in data breaches, financial loss, and reputational damage. The breach of confidentiality could also violate GDPR requirements, exposing organizations to regulatory penalties. Since the vulnerability allows silent monitoring without user consent, detection is challenging, increasing the risk of prolonged undetected espionage or insider threats. Organizations with remote or hybrid workforces using macOS devices are especially vulnerable if devices are not promptly updated. The absence of known exploits in the wild currently reduces immediate risk but does not diminish the urgency of patching, as threat actors may develop exploits rapidly. Overall, the vulnerability undermines trust in macOS security controls and necessitates swift remediation to protect European digital assets and comply with data protection laws.

1. Immediately deploy the security updates released by Apple: macOS Sonoma 14.2, Ventura 13.6.3, and Monterey 12.7.2, across all affected devices within the organization. 2. Enforce strict application control policies using Apple’s Endpoint Security Framework or third-party EDR solutions to monitor and restrict app permissions, especially those requesting accessibility or input monitoring privileges. 3. Conduct regular audits of installed applications and remove any untrusted or unnecessary software that could exploit this vulnerability. 4. Educate users about the risks of installing unverified applications and encourage the use of the Mac App Store or trusted sources only. 5. Implement network monitoring to detect unusual outbound traffic that may indicate data exfiltration attempts following keystroke capture. 6. Utilize macOS’s built-in privacy settings to review and limit apps’ access to input monitoring and accessibility features. 7. Maintain up-to-date backups and incident response plans to quickly recover from potential breaches. 8. Coordinate with IT security teams to integrate this vulnerability into threat hunting and vulnerability management workflows for ongoing vigilance.