CVE-2024-35253 is a vulnerability classified under CWE-59, which pertains to improper link resolution before file access, commonly known as 'link following'. This flaw exists in Microsoft Azure File Sync version 16.0.0 and allows an attacker with low privileges on a system to perform an elevation of privilege attack. The vulnerability arises because the software does not properly validate or resolve symbolic links before accessing files, potentially enabling an attacker to redirect file operations to unintended locations. This can lead to unauthorized modification or replacement of files, compromising system integrity. The CVSS 3.1 base score is 4.4, reflecting a medium severity level, with attack vector local (AV:L), attack complexity high (AC:H), privileges required low (PR:L), and user interaction required (UI:R). The scope is unchanged (S:U), confidentiality impact is none (C:N), integrity impact is high (I:H), and availability impact is none (A:N). The exploitability is considered high due to the need for local access and user interaction, and no known exploits have been reported in the wild as of the publication date. This vulnerability can be leveraged to escalate privileges on systems running the affected Azure File Sync version, potentially allowing attackers to gain higher-level access than originally permitted.

For European organizations, the impact of CVE-2024-35253 can be significant in environments where Azure File Sync is deployed to synchronize files between on-premises servers and Azure cloud storage. An attacker exploiting this vulnerability could modify or replace critical files by abusing symbolic link handling, leading to integrity breaches. This could disrupt business operations, compromise sensitive data, or facilitate further attacks such as lateral movement within networks. Sectors such as finance, healthcare, government, and critical infrastructure that rely heavily on Microsoft cloud services and hybrid storage solutions are particularly at risk. The requirement for local access and user interaction limits remote exploitation but does not eliminate risk, especially in environments with many users or where endpoint security is weak. The vulnerability could also be used as a stepping stone for more severe attacks if combined with other vulnerabilities or social engineering tactics.

1. Monitor Microsoft’s official channels for patches addressing CVE-2024-35253 and apply updates promptly once available. 2. Restrict local user permissions to the minimum necessary, preventing untrusted users from accessing or manipulating Azure File Sync directories. 3. Implement strict file system monitoring and alerting for unusual symbolic link creations or modifications within Azure File Sync directories. 4. Employ endpoint detection and response (EDR) solutions capable of detecting suspicious file system activities related to link following. 5. Educate users about the risks of interacting with untrusted files or links, reducing the likelihood of user interaction exploitation. 6. Consider isolating systems running Azure File Sync to limit the potential impact of privilege escalation. 7. Review and harden group policies and access controls related to file synchronization services. 8. Conduct regular security audits focusing on file integrity and symbolic link usage within critical systems.