CVE-2023-40450 is a security vulnerability in Apple macOS that allows an application to bypass Gatekeeper checks. Gatekeeper is a critical macOS security mechanism that enforces code signing and verifies that applications come from trusted developers before allowing them to run. By bypassing these checks, an attacker can potentially run unsigned or malicious applications without triggering macOS's built-in protections, increasing the risk of malware infection or unauthorized code execution. The vulnerability was identified and addressed by Apple with improved Gatekeeper validation logic, and the fix is included in macOS Sonoma 14. The specific affected versions prior to Sonoma 14 are not detailed, but any macOS version before this update may be vulnerable. There are no known public exploits or reports of active exploitation in the wild, indicating that the vulnerability is not yet weaponized. However, the potential impact is significant because Gatekeeper is a frontline defense against untrusted software. The vulnerability does not require user authentication or interaction beyond app execution, which lowers the barrier for exploitation. The lack of a CVSS score means severity must be assessed based on potential impact and exploitability. Given that bypassing Gatekeeper can lead to execution of malicious code with user privileges, the risk to confidentiality, integrity, and availability is considerable. Organizations relying on macOS systems should prioritize updating to macOS Sonoma 14 and consider additional endpoint security measures to detect unauthorized applications.

For European organizations, this vulnerability poses a risk of unauthorized code execution on macOS endpoints, potentially leading to malware infections, data breaches, or lateral movement within networks. Organizations with a significant macOS user base, such as those in technology, finance, and creative industries, may face increased risk. The bypass of Gatekeeper undermines a key security control that prevents untrusted software from running, increasing the attack surface. This could facilitate targeted attacks, ransomware deployment, or espionage activities. The impact is heightened in environments where macOS devices have access to sensitive data or critical infrastructure. Additionally, the lack of known exploits currently provides a window for proactive mitigation before active exploitation occurs. Failure to patch could lead to increased incident response costs, reputational damage, and regulatory consequences under European data protection laws if breaches occur.

1. Immediately update all macOS devices to macOS Sonoma 14 or later, which contains the fix for this vulnerability. 2. Enforce strict application whitelisting policies using Apple’s built-in tools such as System Policy Control and Endpoint Security Framework to restrict execution of untrusted applications. 3. Implement Mobile Device Management (MDM) solutions to centrally manage macOS updates and security configurations. 4. Monitor endpoint logs and Gatekeeper alerts for signs of suspicious application execution or bypass attempts. 5. Educate users about the risks of running untrusted software and encourage reporting of unusual system behavior. 6. Use additional endpoint protection platforms that can detect anomalous process behavior or unsigned code execution. 7. Regularly audit macOS systems for compliance with security policies and update procedures to ensure timely patch deployment. 8. Consider network segmentation to limit the impact of a compromised macOS device within the corporate environment.