CVE-2021-3187 is a high-severity privilege escalation vulnerability affecting BeyondTrust Privilege Management for Mac versions prior to 5.7. The vulnerability allows an authenticated but unprivileged user to execute a malicious script with root privileges during the installation process. Specifically, the exploit involves placing a script in a temporary directory that is executed as root, thereby elevating the attacker's privileges. This issue is relevant to macOS versions before 10.15.5, including Security Update 2020-003 on Mojave and High Sierra. Later macOS versions are not vulnerable. The vulnerability is categorized under CWE-276, which relates to improper privilege management. The CVSS v3.1 base score is 8.8, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and requiring only low privileges and no user interaction. Although no known exploits are currently reported in the wild, the potential for exploitation exists given the ease of execution and significant impact. This vulnerability is particularly concerning because it allows privilege escalation from an unprivileged user to root, which could lead to full system compromise, unauthorized access to sensitive data, and disruption of system operations.

For European organizations, this vulnerability poses a significant risk, especially those using BeyondTrust Privilege Management for Mac in environments running vulnerable macOS versions. Successful exploitation could allow malicious insiders or compromised user accounts to gain root access, bypassing security controls and potentially leading to data breaches, unauthorized system modifications, or deployment of malware with elevated privileges. This could affect confidentiality of sensitive corporate or customer data, integrity of critical systems, and availability of services. Organizations in sectors with strict regulatory requirements such as finance, healthcare, and government could face compliance violations and reputational damage. Additionally, the ability to escalate privileges without user interaction or complex attack vectors increases the likelihood of exploitation in internal threat scenarios or targeted attacks.

To mitigate this vulnerability, European organizations should: 1) Immediately upgrade BeyondTrust Privilege Management for Mac to version 5.7 or later, which addresses this issue. 2) Ensure all macOS systems are updated to at least version 10.15.5 or later, or have applied Security Update 2020-003 on Mojave and High Sierra. 3) Restrict installation privileges and monitor installation processes to detect unauthorized script execution. 4) Implement strict access controls to limit unprivileged user capabilities and monitor for unusual activity in temporary directories. 5) Employ endpoint detection and response (EDR) solutions capable of detecting privilege escalation attempts. 6) Conduct regular audits of installed software and system configurations to identify vulnerable versions. 7) Educate users and administrators about the risks of running untrusted scripts and the importance of applying security updates promptly.