CVE-2024-55542 is a local privilege escalation vulnerability identified in Acronis Cyber Protect 16 and Acronis Cyber Protect Cloud Agent across Linux, macOS, and Windows platforms. The root cause of this vulnerability is excessive permissions assigned to the Tray Monitor service, which is a component responsible for monitoring and managing backup and protection tasks on the endpoint. Specifically, the vulnerability is categorized under CWE-266, which relates to improper permissions or access control. Because the Tray Monitor service runs with elevated privileges and is granted more permissions than necessary, a local attacker with limited user rights could exploit this flaw to escalate their privileges to a higher level, potentially gaining administrative or root access on the affected system. This could allow the attacker to bypass security controls, manipulate backup data, disable protection mechanisms, or execute arbitrary code with elevated privileges. The affected versions include all builds of Acronis Cyber Protect 16 prior to build 39169 and Acronis Cyber Protect Cloud Agent prior to build 35895. The vulnerability affects all major operating systems supported by these products: Linux, macOS, and Windows. No public exploits have been reported in the wild as of the publication date (January 2, 2025), and no official patches or updates have been linked yet. However, the presence of excessive permissions in a security-critical service represents a significant risk if exploited, especially in environments where these products are widely deployed for backup and cyber protection. The vulnerability requires local access to the system, meaning an attacker must already have some level of user access to the endpoint to leverage this flaw. No user interaction beyond local access is needed, and no network exploitation vector is indicated.

For European organizations, the impact of CVE-2024-55542 could be substantial, particularly in sectors relying heavily on Acronis Cyber Protect 16 for data backup, disaster recovery, and endpoint protection. Successful exploitation could lead to unauthorized privilege escalation, enabling attackers to compromise the confidentiality, integrity, and availability of critical data and systems. This could result in data breaches, tampering with backup archives, disabling of protection mechanisms, and potential lateral movement within corporate networks. Given that Acronis products are often used in regulated industries such as finance, healthcare, and government, the compromise of backup and protection services could lead to regulatory non-compliance, financial losses, and reputational damage. The cross-platform nature of the vulnerability increases the attack surface, affecting diverse IT environments common in European enterprises. Although exploitation requires local access, insider threats or attackers who have gained initial footholds through phishing or other means could leverage this vulnerability to escalate privileges and deepen their control over targeted systems.

1. Immediate mitigation should focus on restricting permissions assigned to the Tray Monitor service to the minimum necessary, following the principle of least privilege. Organizations should audit the permissions of this service and adjust them to prevent unauthorized privilege escalation. 2. Implement strict endpoint access controls and monitoring to detect unusual privilege escalation attempts or unauthorized modifications to the Tray Monitor service. 3. Limit local user accounts and enforce strong authentication policies to reduce the risk of local attackers gaining initial access. 4. Employ application whitelisting and integrity monitoring to detect unauthorized changes to Acronis components. 5. Until official patches are released, consider isolating critical systems running affected Acronis products or deploying compensating controls such as enhanced logging and alerting on privilege escalation events. 6. Maintain up-to-date backups stored offline or in immutable storage to ensure recovery in case of compromise. 7. Engage with Acronis support and monitor vendor communications closely for forthcoming patches or updates addressing this vulnerability.