CVE-2022-33876 in FortiADC
Summary
by MITRE • 12/06/2022
Multiple instances of improper input validation vulnerability in Fortinet FortiADC version 7.1.0, version 7.0.0 through 7.0.2 and version 6.2.4 and below allows an authenticated attacker to retrieve files with specific extension from the underlying Linux system via crafted HTTP requests.
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Analysis
by VulDB Data Team • 01/01/2023
The vulnerability identified as CVE-2022-33876 represents a critical improper input validation flaw within Fortinet FortiADC appliances, specifically affecting versions 7.1.0, 7.0.0 through 7.0.2, and 6.2.4 and earlier. This security weakness stems from inadequate validation of user-supplied input within the application's HTTP request processing mechanisms, creating a pathway for authenticated attackers to exploit the system's file retrieval capabilities. The flaw manifests when the appliance fails to properly sanitize or validate file path parameters in HTTP requests, allowing malicious users to construct requests that can traverse the file system and access sensitive files with predetermined extensions.
The technical implementation of this vulnerability resides in the application's handling of file access requests through HTTP protocols, where the FortiADC system does not adequately filter or validate the file path components submitted by clients. This allows an authenticated attacker to craft specific HTTP requests that can bypass normal access controls and directly access files on the underlying Linux operating system. The vulnerability specifically targets file retrieval operations where the system processes requests for files with certain extensions, enabling attackers to potentially access configuration files, log files, or other sensitive system data that should remain protected from unauthorized access. The flaw operates at the application layer and can be exploited through standard HTTP protocols, making it particularly dangerous as it requires minimal specialized tools to execute.
The operational impact of this vulnerability extends beyond simple data exposure, as it provides attackers with potential access to critical system information that could aid in further exploitation attempts. An authenticated attacker with access to the FortiADC appliance can leverage this vulnerability to retrieve sensitive files that may contain system configurations, user credentials, or other confidential data that could be used to escalate privileges or conduct additional attacks against the network infrastructure. The implications are particularly severe given that FortiADC appliances typically serve as critical components in application delivery and load balancing within enterprise environments, making the compromise of such systems potentially disruptive to business operations. This vulnerability aligns with CWE-20, which describes improper input validation as a fundamental weakness in software design that allows malicious input to be processed without adequate sanitization, and can be categorized under ATT&CK technique T1078 for valid accounts and T1566 for credential access through application exploitation.
Organizations affected by this vulnerability should implement immediate mitigation strategies including applying the latest security patches provided by Fortinet, which address the input validation deficiencies in the affected versions. Network segmentation and access controls should be strengthened to limit the scope of potential exploitation, ensuring that only authorized personnel can access the FortiADC appliances. Additionally, implementing web application firewalls and monitoring systems that can detect and block suspicious file access patterns can provide additional layers of protection against exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify any potential variants or related vulnerabilities within the FortiADC platform or associated systems. The remediation process should also include reviewing and updating access controls, ensuring that only necessary administrative accounts have access to the appliance, and implementing proper logging and monitoring of file access operations to detect any unauthorized attempts to retrieve system files.