CVE-2020-28908 in Fusion
Summary
by MITRE • 05/24/2021
Command Injection in Nagios Fusion 4.1.8 and earlier allows for Privilege Escalation to nagios.
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Analysis
by VulDB Data Team • 05/27/2021
The vulnerability identified as CVE-2020-28908 represents a critical command injection flaw within Nagios Fusion version 4.1.8 and earlier systems. This vulnerability resides in the web-based administration interface of the Nagios monitoring solution, specifically affecting the way the application processes user input when executing system commands. The flaw stems from insufficient input validation and sanitization mechanisms that fail to properly escape or filter malicious command sequences submitted through web forms or API endpoints. Attackers can exploit this vulnerability by crafting specially formatted input that gets directly executed within the system shell, bypassing normal authentication and authorization controls.
The technical implementation of this vulnerability aligns with CWE-77 and CWE-88 categories, representing command injection flaws that allow arbitrary code execution. The vulnerability operates at the application layer where user-supplied parameters are concatenated directly into system command strings without proper sanitization. When legitimate users with administrative privileges submit commands through the Fusion interface, the application fails to validate the input properly, enabling attackers to inject malicious shell commands that execute with the privileges of the web server process. This particular implementation targets the nagios user account which typically runs with elevated privileges necessary for system monitoring operations.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise. An attacker who successfully exploits this vulnerability can execute arbitrary commands on the target system with the privileges of the nagios user, potentially gaining access to sensitive monitoring data, modifying system configurations, or establishing persistent backdoors. The privilege escalation aspect means that even if an attacker initially gains access through a lower-privileged account, they can leverage this vulnerability to elevate their access level and achieve full administrative control over the monitoring infrastructure. This creates a significant risk for organizations that rely on Nagios Fusion for critical system monitoring and security operations.
Security practitioners should implement immediate mitigations including upgrading to Nagios Fusion version 4.1.9 or later, which contains patches addressing the command injection vulnerability. Network segmentation and firewall rules should be configured to restrict access to the Nagios Fusion administration interface to authorized personnel only, reducing the attack surface. Input validation and sanitization measures should be enhanced throughout the application to prevent any future injection attacks. The ATT&CK framework categorizes this vulnerability under T1059.001 (Command and Scripting Interpreter: PowerShell) and T1068 (Exploitation for Privilege Escalation) techniques, emphasizing the need for comprehensive defensive strategies including regular security assessments, intrusion detection systems, and monitoring for anomalous command execution patterns. Organizations should also consider implementing application whitelisting policies and privilege separation to limit the potential impact of such vulnerabilities.