CVE-2020-15901 in Nagios XI
Summary
by MITRE
ajaxhelper.php in Nagios XI before 5.7.2 allows remote attackers to execute arbitrary commands via cmdsubsys.
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Analysis
by VulDB Data Team • 07/23/2020
The vulnerability identified as CVE-2020-15901 affects Nagios XI versions prior to 5.7.2 and resides within the ajaxhelper.php component. This represents a critical command injection flaw that enables remote attackers to execute arbitrary system commands on the affected server. The vulnerability stems from insufficient input validation and sanitization within the cmdsubsys parameter processing functionality, creating an avenue for malicious command execution without authentication requirements.
The technical implementation of this vulnerability demonstrates a classic command injection attack vector where user-controllable input flows directly into system command execution contexts. The ajaxhelper.php script processes the cmdsubsys parameter without proper sanitization, allowing attackers to inject malicious commands that get executed by the underlying operating system. This flaw operates at the application layer and can be exploited through HTTP requests targeting the vulnerable endpoint, making it particularly dangerous for network-accessible systems.
From an operational impact perspective, this vulnerability exposes organizations to significant security risks including complete system compromise, data exfiltration, and lateral movement within network environments. Attackers can leverage this vulnerability to gain unauthorized access to the server, escalate privileges, install backdoors, or conduct further reconnaissance activities. The remote nature of the exploit means that attackers do not require physical access or prior authentication credentials to exploit the vulnerability, amplifying the potential damage.
The vulnerability aligns with CWE-77 and CWE-94 categories within the Common Weakness Enumeration framework, specifically addressing command injection and code injection weaknesses. From the MITRE ATT&CK framework perspective, this vulnerability maps to techniques such as T1059.001 (Command and Scripting Interpreter: PowerShell) and T1068 (Exploitation for Privilege Escalation) as attackers can leverage the command execution capability to escalate their privileges and persist within the compromised environment. Organizations using Nagios XI systems are particularly vulnerable as this tool is commonly deployed for network monitoring and system administration, making the attack surface significant.
Mitigation strategies should prioritize immediate patching of Nagios XI to version 5.7.2 or later, which contains the necessary fixes for the command injection vulnerability. Network segmentation and firewall rules should be implemented to restrict access to the affected endpoint, while input validation mechanisms should be strengthened to prevent similar issues in other applications. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar injection vulnerabilities across the organization's infrastructure, ensuring comprehensive protection against command injection attacks.