CVE-2019-20197 in Nagios XI
Summary
by MITRE
In Nagios XI 5.6.9, an authenticated user is able to execute arbitrary OS commands via shell metacharacters in the id parameter to schedulereport.php, in the context of the web-server user account.
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Analysis
by VulDB Data Team • 03/19/2024
This vulnerability exists within Nagios XI version 5.6.9, a widely deployed network monitoring and management platform that provides critical infrastructure visibility for organizations. The flaw represents a severe command injection vulnerability that allows authenticated users to escalate their privileges and execute arbitrary operating system commands on the underlying server. The vulnerability specifically manifests in the schedulereport.php script which processes user input through the id parameter without proper sanitization or validation, creating a direct pathway for malicious command execution.
The technical exploitation occurs through shell metacharacters that are not properly escaped or filtered in the id parameter processing. When an authenticated user submits crafted input containing shell metacharacters such as semicolons, ampersands, or backticks, these characters are interpreted by the underlying shell and executed with the privileges of the web server process. This creates a critical privilege escalation vector where the attacker can execute commands as the web server user, typically with elevated system permissions. The vulnerability falls under CWE-78 which specifically addresses OS Command Injection, a well-documented weakness in software applications that fail to properly sanitize user inputs before passing them to system commands.
The operational impact of this vulnerability is substantial as it provides attackers with a foothold to compromise the entire monitoring infrastructure. An authenticated user can leverage this vulnerability to gain access to sensitive system information, modify monitoring configurations, exfiltrate data, or establish persistence mechanisms. The web server user account typically has access to configuration files, database connections, and potentially other system resources that could be exploited for further lateral movement within the network. This vulnerability directly maps to ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries execute code through the command line interface.
Organizations using Nagios XI 5.6.9 should immediately apply the vendor-provided security patches and updates to remediate this vulnerability. Additionally, implementing network segmentation to limit access to the Nagios XI interface, enforcing strict input validation and sanitization measures, and monitoring for suspicious command execution patterns can help reduce the risk. Regular security assessments and vulnerability scanning should be conducted to identify similar injection vulnerabilities in other applications and services within the infrastructure. The vulnerability highlights the critical importance of proper input validation and the principle of least privilege in system design, particularly for applications handling sensitive monitoring data and system-level operations.