CVE-2024-40843 is a vulnerability identified in Apple macOS that allows an application to modify protected parts of the file system due to insufficient access control checks. The root cause is a failure to properly enforce permissions, categorized under CWE-863 (Improper Authorization). This flaw enables an app with limited privileges to escalate its rights and alter critical system files or directories, potentially undermining system integrity. The vulnerability does not require user interaction (UI:N) but does require local privileges (PR:L) and has low attack complexity (AC:L), meaning an attacker with some access can exploit it without sophisticated techniques. The vulnerability affects macOS versions prior to the release of macOS Sequoia 15, which includes the fix through improved checks. The CVSS v3.1 base score is 5.5 (medium severity), reflecting the impact on integrity (I:H) but no impact on confidentiality (C:N) or availability (A:N). No known exploits have been reported in the wild, suggesting limited current exploitation but a potential risk if attackers develop techniques to leverage this flaw. The vulnerability could be used by malicious insiders or attackers who have gained limited access to escalate privileges and compromise system files, potentially leading to persistence, tampering, or further attacks on the system.

For European organizations, this vulnerability poses a risk primarily to the integrity of macOS systems. Attackers with local access and limited privileges could modify protected system files, potentially leading to unauthorized persistence mechanisms, tampering with security controls, or disabling security features. This could facilitate further attacks or data manipulation. Organizations relying on macOS for critical operations, including government agencies, financial institutions, and technology companies, could face operational disruptions or targeted attacks exploiting this flaw. Although confidentiality and availability are not directly impacted, the integrity compromise could indirectly affect these areas if attackers leverage the vulnerability to implant malware or disrupt system functions. The absence of known exploits reduces immediate risk, but the medium severity and ease of exploitation by local users warrant prompt attention. European organizations with remote or hybrid workforces using macOS devices may also face increased exposure if endpoint security is insufficient.

The primary mitigation is to upgrade all affected macOS systems to macOS Sequoia 15 or later, where the vulnerability is fixed. Organizations should enforce strict application whitelisting and endpoint protection policies to limit the installation and execution of untrusted or unauthorized applications. Implementing least privilege principles for user accounts reduces the risk of exploitation by limiting local privileges. Regularly auditing system file integrity and monitoring for unauthorized changes can help detect exploitation attempts. Additionally, organizations should ensure that remote access to macOS devices is tightly controlled and monitored, reducing the risk of attackers gaining local access. Security teams should stay informed about any emerging exploit reports related to this CVE and apply security patches promptly. Training users to recognize suspicious behavior and maintaining robust incident response plans are also recommended.