CVE-2022-27489 in FortiExtender
Summary
by MITRE • 02/16/2023
A improper neutralization of special elements used in an os command ('os command injection') in Fortinet FortiExtender 7.0.0 through 7.0.3, 5.3.2, 4.2.4 and below allows attacker to execute unauthorized code or commands via crafted HTTP requests.
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Analysis
by VulDB Data Team • 03/16/2023
The vulnerability identified as CVE-2022-27489 represents a critical operating system command injection flaw affecting Fortinet FortiExtender devices across multiple versions including 7.0.0 through 7.0.3, 5.3.2, and 4.2.4 and below. This security weakness falls under the Common Weakness Enumeration category CWE-77, which specifically addresses improper neutralization of special elements used in operating system commands. The vulnerability arises from insufficient input validation and sanitization within the web interface of FortiExtender devices, creating an exploitable entry point for malicious actors to inject arbitrary operating system commands.
The technical exploitation of this vulnerability occurs through crafted HTTP requests that bypass normal authentication mechanisms and input validation controls. When the FortiExtender device processes these malicious requests, it fails to properly sanitize user-supplied input before executing system commands, allowing attackers to inject OS-level commands that are subsequently executed with the privileges of the web server process. This command injection vulnerability enables attackers to execute unauthorized code on the affected device, potentially leading to complete system compromise and unauthorized access to network resources.
The operational impact of this vulnerability extends beyond simple command execution, as it provides attackers with a pathway to escalate privileges and gain persistent access to the network infrastructure. Attackers can leverage this vulnerability to perform reconnaissance activities, install backdoors, modify system configurations, or redirect network traffic through the compromised FortiExtender device. The affected versions span multiple major releases, indicating a widespread exposure across Fortinet's product line, which increases the potential attack surface significantly. Organizations utilizing these devices face substantial risk of unauthorized network access, data exfiltration, and potential lateral movement within their network environments.
Mitigation strategies for CVE-2022-27489 should prioritize immediate firmware updates from Fortinet to address the identified command injection vulnerability. Organizations must also implement network segmentation and access controls to limit exposure of FortiExtender devices to untrusted networks. Additional defensive measures include monitoring network traffic for suspicious command execution patterns, implementing web application firewalls to detect and block malicious HTTP requests, and conducting regular security assessments of network infrastructure. The vulnerability demonstrates the importance of proper input validation and output encoding as outlined in the OWASP Top Ten security principles, particularly focusing on command injection prevention techniques. Network administrators should also consider implementing intrusion detection systems to monitor for exploitation attempts and establish incident response procedures to address potential compromise of these critical network devices.