CVE-2024-27886 is a logic flaw in Apple macOS that allows an unprivileged application to capture keystrokes from other applications, including those that use secure input mode designed to protect sensitive input such as passwords. The vulnerability stems from improper enforcement of input restrictions, enabling an attacker to bypass macOS's secure input protections. This issue affects macOS versions before 14.4 (Sonoma), where Apple has implemented improved restrictions to resolve the problem. The vulnerability does not require any privileges or user interaction to exploit, making it particularly dangerous. The CVSS v3.1 score of 7.5 reflects a network attack vector with low complexity, no privileges required, no user interaction, and a significant impact on integrity (keystroke logging), though confidentiality impact is not directly indicated as compromised in the CVSS vector. However, keystroke logging inherently risks confidentiality of user input. No known exploits have been reported in the wild yet, but the potential for abuse is high given the nature of the flaw. The vulnerability is classified under CWE-783 (Operator Precedence Logic Error), indicating a logic error in the code that leads to incorrect enforcement of security controls. This vulnerability could be leveraged by malicious actors to harvest sensitive credentials, personal data, or other confidential information entered via keyboard, undermining user and organizational security.

For European organizations, the ability of an unprivileged app to log keystrokes across applications, including those using secure input mode, poses a severe threat to data confidentiality and user privacy. Sensitive information such as passwords, encryption keys, and confidential communications could be intercepted without detection. This risk is particularly acute for sectors like finance, healthcare, government, and critical infrastructure where macOS devices are used. The breach of input confidentiality could lead to unauthorized access to corporate networks, data exfiltration, and compromise of secure communications. Additionally, the lack of required privileges or user interaction lowers the barrier for attackers, increasing the likelihood of exploitation. The vulnerability could also undermine trust in macOS security features, potentially impacting compliance with European data protection regulations such as GDPR. Organizations relying on macOS for secure operations must consider this vulnerability a significant risk to their security posture.

The primary mitigation is to update all affected macOS systems to version 14.4 (Sonoma) or later, where Apple has fixed the logic issue. Organizations should prioritize patch deployment across all macOS endpoints, especially those handling sensitive data. In addition to patching, implement application control policies to restrict installation and execution of untrusted or unverified applications that could exploit this vulnerability. Employ endpoint detection and response (EDR) solutions capable of monitoring for anomalous input logging behaviors or unauthorized access to input APIs. Educate users about the risks of installing unknown software and encourage adherence to least privilege principles. Network segmentation and limiting exposure of macOS devices to untrusted networks can reduce attack surface. Regularly audit installed applications and monitor system logs for suspicious activity related to input capture. Finally, consider deploying multi-factor authentication (MFA) to mitigate the impact of credential compromise resulting from keystroke logging.