Published on: 2025-04-12

Intelligence Report: Symbolic Link trick lets attackers bypass FortiGate patches Fortinet warns – Securityaffairs.com

1. BLUF (Bottom Line Up Front)

Fortinet has identified a vulnerability exploitation method that allows threat actors to maintain read-only access to FortiGate devices, even after patches for known vulnerabilities have been applied. This method involves the use of symbolic links in SSL-VPN language folders, posing a persistent security risk. Immediate mitigation strategies include deploying AV/IPS signatures and ensuring all devices are updated with the latest FortiOS versions. Stakeholders are advised to prioritize patch management and review device configurations to prevent unauthorized access.

2. Detailed Analysis

The following structured analytic techniques have been applied for this analysis:

General Analysis

The exploitation of FortiGate devices through symbolic links represents a sophisticated method of maintaining unauthorized access. Attackers leveraged vulnerabilities such as CVE-2022-42475, CVE-2023-27997, and CVE-2024-21762 to create symbolic links that connect user and root filesystems. This technique allows for persistent access, circumventing traditional patching processes. The attack is not geographically or industry-specific, indicating a broad threat landscape. Fortinet’s response includes updating detection mechanisms and advising customers on patching practices.

3. Implications and Strategic Risks

The persistence of unauthorized access to FortiGate devices poses significant risks to national security and economic interests. The ability of threat actors to bypass patches undermines confidence in cybersecurity measures and could lead to data breaches, loss of sensitive information, and potential disruptions in critical infrastructure. The widespread nature of the attack suggests a need for heightened vigilance across all sectors utilizing FortiGate devices.

4. Recommendations and Outlook

Recommendations:

• Conduct comprehensive audits of all FortiGate devices to identify and remove unauthorized symbolic links.
• Enhance monitoring and logging capabilities to detect anomalous activities related to symbolic link creation.
• Implement regular training for IT staff on emerging cybersecurity threats and mitigation techniques.
• Advocate for regulatory frameworks that mandate timely patch management and vulnerability disclosures.

Outlook:

In the best-case scenario, organizations promptly implement Fortinet’s recommendations, significantly reducing the risk of unauthorized access. In the worst-case scenario, failure to address the vulnerability could lead to widespread data breaches and operational disruptions. The most likely outcome involves a gradual improvement in security posture as awareness and mitigation efforts increase.

5. Key Individuals and Entities

The report mentions Fortinet as the primary entity involved in identifying and addressing the vulnerability. No specific individuals are referenced in the context of this report.