CVE-2025-12838 is a local privilege escalation vulnerability identified in MSP360 Free Backup version 8.1.0.620, classified under CWE-59 (Improper Link Resolution Before File Access). The flaw exists in the restore functionality, where the software improperly handles junction points (a type of symbolic link in Windows). An attacker who already has the ability to execute low-privileged code on the system can create a malicious junction point that the backup service follows during restore operations. This improper link resolution allows the attacker to trick the service into creating or overwriting arbitrary files with elevated SYSTEM privileges. Exploiting this vulnerability requires two conditions: the attacker must have local code execution capabilities with low privileges, and an administrator must perform some interaction, likely initiating or approving a restore operation. Successful exploitation results in arbitrary code execution with SYSTEM-level privileges, enabling complete control over the affected system. Although no public exploits are known at this time, the vulnerability's CVSS score of 7.3 reflects its high impact on confidentiality, integrity, and availability. The vulnerability was reserved and published by the Zero Day Initiative (ZDI) under identifier ZDI-CAN-27245, indicating credible research and validation. The lack of available patches at the time of disclosure necessitates immediate risk mitigation through operational controls.

For European organizations, this vulnerability poses a significant risk, especially in environments where MSP360 Free Backup is deployed for critical data protection. Successful exploitation can lead to full system compromise, allowing attackers to access sensitive data, disrupt backup and restore processes, and potentially move laterally within networks. This can undermine business continuity and data integrity, impacting sectors such as finance, healthcare, and government services that rely heavily on backup solutions. The requirement for local code execution and administrative interaction limits remote exploitation but does not eliminate risk, particularly in organizations with inadequate endpoint security or insider threats. The high severity rating underscores the potential for serious operational and reputational damage. Organizations with MSP360 Free Backup installations should assess their exposure and prioritize mitigation to prevent privilege escalation attacks that could facilitate broader intrusions.

1. Restrict local user permissions rigorously to prevent unauthorized code execution, especially on systems running MSP360 Free Backup. 2. Implement strict administrative controls and minimize the number of users with restore operation privileges to reduce the risk of malicious or accidental exploitation. 3. Monitor file system activities for suspicious creation of junction points or symbolic links, particularly in directories used by MSP360 for restore operations. 4. Employ application whitelisting and endpoint detection and response (EDR) solutions to detect and block attempts to exploit this vulnerability. 5. Isolate backup servers and restrict network access to trusted administrators only, reducing the attack surface. 6. Stay informed on vendor advisories and apply patches or updates promptly once released. 7. Conduct regular security training to raise awareness about the risks of local privilege escalation and the importance of cautious administrative interactions. 8. Consider implementing multi-factor authentication for administrative actions related to backup and restore processes to add an additional security layer.