CVE-2022-42475 Vulnerability: Analysis, Impact, Mitigation

What is CVE-2022-42475 vulnerability?

The CVE-2022-42475 vulnerability is a critical heap-based buffer overflow flaw in the SSL-VPN module of Fortinet’s FortiOS. It allows remote attackers to execute arbitrary code on vulnerable systems without authentication, providing a potential entry point for fileless malware attacks. Classified as a Remote Code Execution (RCE) vulnerability, it poses significant risks by enabling complete system compromise when exploited.

When was it discovered?

The CVE-2022-42475 vulnerability was disclosed publicly on December 12, 2022, by Fortinet following observations of in-the-wild exploitation. FortiGuard Labs credited their internal team with discovering this vulnerability, and a public advisory was issued shortly afterward to safeguard users and systems.

Affected products & versions

Product	Versions Affected	Fixed Versions / Patch Links
FortiOS	7.2.0 - 7.2.2	FortiOS 7.2.3 Patch
	7.0.0 - 7.0.8	FortiOS 7.0.9 Patch

CVE-2022-42475 technical description

The CVE-2022-42475 vulnerability arises from improper validation of buffer boundaries within the SSL-VPN module of FortiOS. By sending specially crafted packets to the SSL-VPN interface, attackers can trigger a heap-based buffer overflow, leading to code execution at the system level. Exploitation typically involves bypassing authentication, utilizing crafted payloads to corrupt memory, and executing malicious shells. The vulnerability is critical due to the potential stealthiness of its use in targeted attacks, where fileless malware and advanced persistence techniques are implemented.

Tactics, Techniques & Procedures (TTPs)

Attackers leveraging CVE-2022-42475 often incorporate spear-phishing campaigns or malicious payload dropper tactics to exploit the SSL-VPN service. Advanced obfuscation and use of living-off-the-land binaries (LOLBins) have been observed in these attacks, indicating a reliance on covert methods to maintain persistence.

Indicators of compromise

Detecting exploitation may involve monitoring anomalous activity such as unexpected SSL-VPN logins, abnormal network traffic patterns on TCP/SSL ports, or the appearance of malicious shell artifacts in critical server paths. IPs linked with command-and-control (C2) hosts should also be analyzed for associations with previously documented campaigns.

Known proof-of-concepts & exploits

Exploitation frameworks targeting CVE-2022-42475 include both public proof-of-concept scripts on platforms like GitHub and documented techniques observed in state-sponsored campaigns. Researchers have linked this vulnerability to an advanced persistent threat (APT) group utilizing backdoor deployments.

How to detect CVE-2022-42475 vulnerability

Detection strategies include leveraging EDR solutions, creating specific SIEM alerts for malformed SSL-VPN packets, and monitoring system logs for suspicious activity. Security teams may analyze crash dumps for signs of memory corruption or stack traces indicative of buffer overflow attempts.

Impact & risk of CVE-2022-42475 vulnerability

This vulnerability poses a significant threat to data confidentiality, system integrity, and availability. When exploited, attackers can gain control over sensitive information, disable key infrastructure, or pivot to lateral attacks across a network. Organizations failing to address this vulnerability risk catastrophic data breaches, operational downtime, and compliance violations.

Mitigation & remediation strategies

Update affected systems to the latest patched FortiOS versions (7.2.3 or 7.0.9) as recommended by Fortinet. Disable SSL-VPN services on vulnerable systems where updates cannot be immediately applied. Regularly audit configurations to ensure exposed interfaces are minimized, and implement segmentation strategies to limit attack surfaces.

CVE-2022-42475 Vulnerability FAQs

CVE-2022-42475 is a critical buffer overflow vulnerability in Fortinet’s FortiOS SSL-VPN module. It works by allowing attackers to send crafted packets that exploit memory management flaws, leading to remote code execution on the system.

Attackers exploit CVE-2022-42475 by targeting the exposed SSL-VPN module of FortiOS installations. Specifically, it involves sending malicious payloads designed to manipulate heap memory vulnerabilities, granting access to unauthorized remote control.

While patches have been released for CVE-2022-42475, unpatched systems remain vulnerable even years after its disclosure. Legacy systems or misconfigurations could still present active threats if mitigations are not applied.

Organizations can safeguard against CVE-2022-42475 by promptly applying security patches, disabling SSL-VPN where unnecessary, and employing continuous monitoring tools to identify and mitigate exploitation attempts.