In recent years, VPN vulnerabilities have emerged as a critical threat vector for organizations worldwide.
Threat actors, including both cybercriminal groups and state-sponsored entities, are increasingly exploiting these vulnerabilities to gain unauthorized access to sensitive networks.
Two notable vulnerabilities, CVE-2018-13379 and CVE-2022-40684, have become staples in the attacker’s playbook, allowing for large-scale credential theft and administrative control over VPN infrastructure.
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Exploitation Tactics and Impact
CVE-2018-13379, a path traversal vulnerability in Fortinet’s FortiGate SSL VPN devices, remains a favorite among attackers due to its simplicity and effectiveness.
This vulnerability allows for direct, unauthenticated access to sensitive system files, including plaintext VPN credentials.
Despite being nearly five years old, it continues to be exploited, often through automated proof-of-concept (PoC) exploits that streamline credential theft on a massive scale.
According to Relia Quest Report, this vulnerability has been used by state-sponsored groups like APT28 and MuddyWater for long-term espionage, while cybercriminals focus on monetizing stolen credentials through ransomware or dark-web sales.
CVE-2022-40684, an authentication bypass vulnerability in Fortinet FortiOS, FortiProxy, and FortiManager devices, offers attackers administrator-level access without requiring valid credentials.
This level of control enables threat actors to manipulate device configurations, extract sensitive data, and deploy malicious policies for sustained network dominance.
The Belsen_Group, a threat actor, exploited this vulnerability in a breach affecting over 15,000 FortiGate devices worldwide, highlighting the scale and persistence of such attacks.
The Role of AI and Automation
The rise of AI and automation is amplifying the scale and sophistication of VPN attacks.
AI-powered tools can automate phishing campaigns and brute-force attacks for credential harvesting, while large language models (LLMs) analyze credential dumps to identify high-value targets almost instantly.
This technological advancement is expected to streamline both credential-based and infrastructure-level attacks, forcing organizations to adopt AI-driven defenses and automate detection processes.
To counter these threats, organizations must prioritize patching vulnerabilities, enforcing multi-factor authentication (MFA), and segmenting critical systems to limit lateral movement.
Additionally, implementing out-of-band secondary authentication and conducting regular configuration audits can help prevent credential theft and further exploitation.
As VPN infrastructure becomes a focal point for hybrid cyber operations, proactive measures are crucial to protect against these evolving threats.
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