CVE-2020-28901 in Fusion
Summary
by MITRE • 05/24/2021
Command Injection in Nagios Fusion 4.1.8 and earlier allows for Privilege Escalation or Code Execution as root via vectors related to corrupt component installation in cmd_subsys.php.
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Analysis
by VulDB Data Team • 05/27/2021
The vulnerability identified as CVE-2020-28901 represents a critical command injection flaw within Nagios Fusion versions 4.1.8 and earlier. This security weakness stems from improper input validation and sanitization within the cmd_subsys.php component, which processes system commands during component installation procedures. The vulnerability specifically affects the handling of user-supplied data during the installation of corrupted components, creating an avenue for malicious actors to execute arbitrary commands with elevated privileges. The flaw exists in the software's privilege management system where legitimate administrative operations are not properly isolated from potentially malicious inputs, allowing unauthorized command execution in the context of the root user.
Technical exploitation of this vulnerability occurs through the manipulation of component installation parameters within the cmd_subsys.php file. When Nagios Fusion processes corrupted component installations, the system fails to adequately sanitize command arguments that are passed to underlying system functions. This creates a command injection scenario where attacker-controlled input can be interpreted and executed as shell commands by the system. The vulnerability is particularly dangerous because it operates at the core of the application's installation and management subsystems, where legitimate administrative commands are processed. The lack of proper input validation and command escaping mechanisms allows attackers to inject malicious payloads that can execute with the highest available privileges, effectively compromising the entire system. This flaw aligns with CWE-77 and CWE-88 categories related to command injection vulnerabilities, where insufficient sanitization of user inputs leads to arbitrary code execution.
The operational impact of CVE-2020-28901 extends beyond simple code execution to encompass complete system compromise and privilege escalation. Attackers who successfully exploit this vulnerability can execute commands as the root user, gaining unrestricted access to all system resources, files, and services. This level of access enables comprehensive system infiltration including data exfiltration, lateral movement within network environments, and establishment of persistent backdoors. The vulnerability's presence in the component installation subsystem means that even legitimate administrative operations could be compromised, creating a persistent threat vector that could be exploited repeatedly. Organizations running affected Nagios Fusion versions face significant risk of complete system compromise, with potential impacts including data loss, service disruption, and unauthorized access to sensitive network infrastructure. The vulnerability's exploitation can be achieved through various attack vectors including web interface manipulation, API calls, or any method that can trigger the affected component installation process.
Mitigation strategies for CVE-2020-28901 must address both immediate remediation and long-term security hardening measures. The primary and most effective mitigation involves upgrading to Nagios Fusion version 4.1.9 or later, which contains patches specifically addressing the command injection vulnerability in cmd_subsys.php. Organizations should also implement network segmentation and access controls to limit exposure of Nagios Fusion installations to trusted users only. Additional protective measures include implementing web application firewalls to monitor and filter suspicious command execution patterns, conducting regular security audits of system components, and establishing robust input validation procedures for all user-supplied data. Security teams should also consider implementing monitoring solutions that can detect anomalous command execution patterns indicative of exploitation attempts. The vulnerability's classification under ATT&CK technique T1059.001 for command and scripting interpreter highlights the importance of implementing strict command execution policies and privilege separation. Organizations must also ensure that all administrative operations are performed with the principle of least privilege, reducing the potential impact of successful exploitation attempts. Regular vulnerability assessments and penetration testing should be conducted to identify similar weaknesses in related systems and applications within the network infrastructure.