CVE-2022-23447 in FortiExtender Management Interface
Summary
by MITRE • 07/11/2023
An improper limitation of a pathname to a restricted directory ('Path Traversal') vulnerability [CWE-22] in FortiExtender management interface 7.0.0 through 7.0.3, 4.2.0 through 4.2.4, 4.1.1 through 4.1.8, 4.0.0 through 4.0.2, 3.3.0 through 3.3.2, 3.2.1 through 3.2.3, 5.3 all versions may allow an unauthenticated and remote attacker to retrieve arbitrary files from the underlying filesystem via specially crafted web requests.
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Analysis
by VulDB Data Team • 07/11/2023
The CVE-2022-23447 vulnerability represents a critical path traversal flaw in FortiExtender management interfaces across multiple version ranges, fundamentally compromising the security posture of affected devices. This vulnerability falls under CWE-22, which specifically addresses improper limitation of pathname to restricted directories, a well-documented class of vulnerabilities that has been consistently flagged as high-risk across industry security frameworks. The flaw exists within the web management interface of FortiExtender devices, creating an avenue for attackers to bypass normal file access controls and directly access files within the underlying operating system's filesystem. The vulnerability's impact is particularly severe because it requires no authentication, making it exploitable by any remote attacker who can access the device's management interface. This unauthenticated nature significantly broadens the attack surface and eliminates the need for prior compromise or credential theft, which aligns with tactics commonly employed in initial access phases of cyber operations as outlined in the MITRE ATT&CK framework under initial access techniques.
The technical implementation of this path traversal vulnerability allows attackers to manipulate file path parameters in web requests to navigate beyond the intended directory boundaries and access arbitrary files on the device's filesystem. This typically occurs when user-supplied input is not properly sanitized or validated before being used in file system operations. The vulnerability affects multiple major version lines including 3.x, 4.x, 5.x, and 7.x series of FortiExtender firmware, indicating a widespread issue that has persisted across several releases. Attackers can exploit this weakness to retrieve sensitive configuration files, authentication credentials, system logs, and potentially other system files that could reveal critical information about the device's configuration and operational state. The remote exploit capability means that attackers do not need physical access to the device or network proximity, as the vulnerability can be leveraged through standard web browser access to the management interface. This characteristic places the vulnerability in the category of remotely exploitable flaws that can be weaponized at scale, as demonstrated by various threat actors who have historically targeted such vulnerabilities in network infrastructure devices.
The operational impact of CVE-2022-23447 extends beyond simple unauthorized file access, as it can enable attackers to gain deeper insights into the network infrastructure and potentially facilitate further exploitation. Successful exploitation could lead to the disclosure of sensitive information such as administrative credentials, network configuration details, and device-specific parameters that could be used for privilege escalation or lateral movement within the network. The vulnerability's presence in FortiExtender devices, which are commonly used for remote network connectivity and site-to-site connections, creates additional risks for organizations that rely on these devices for their network infrastructure. The affected versions span multiple years of development, suggesting that this vulnerability has been present for an extended period, potentially providing attackers with ample time to develop and deploy exploits. Organizations using these devices face increased risk of data breaches, network compromise, and potential regulatory compliance violations, particularly in environments where strict data protection requirements are enforced. The vulnerability's classification as a path traversal issue also means that it could potentially be chained with other exploits to achieve more sophisticated attack objectives, as outlined in various ATT&CK framework techniques related to privilege escalation and defense evasion.
Mitigation strategies for CVE-2022-23447 should prioritize immediate firmware updates from Fortinet to address the root cause of the vulnerability. Organizations should also implement network segmentation and access controls to limit exposure of FortiExtender management interfaces to trusted networks only. The implementation of web application firewalls and input validation controls can provide additional layers of protection against path traversal attacks. Regular security assessments and vulnerability scanning should be conducted to identify any remaining unpatched devices within the network infrastructure. Network monitoring should be enhanced to detect anomalous access patterns that might indicate exploitation attempts. Given the vulnerability's remote and unauthenticated nature, organizations should also consider implementing network access controls such as firewalls to restrict access to management ports and interfaces. The remediation process should include comprehensive testing of updated firmware to ensure that the patch does not introduce compatibility issues with existing network configurations, while also verifying that the vulnerability has been properly addressed through independent validation. Security teams should also review and update their incident response procedures to account for potential exploitation of this vulnerability, ensuring that appropriate detection and response capabilities are in place to quickly identify and remediate any successful exploitation attempts.