CVE-2021-37348 in Nagios XI
Summary
by MITRE • 08/13/2021
Nagios XI before version 5.8.5 is vulnerable to local file inclusion through improper limitation of a pathname in index.php.
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Analysis
by VulDB Data Team • 08/18/2021
Nagios XI versions prior to 5.8.5 contain a critical local file inclusion vulnerability that stems from insufficient validation of user-supplied input in the index.php script. This flaw allows attackers with local access to manipulate file path parameters and potentially include arbitrary local files on the system. The vulnerability specifically manifests when the application fails to properly sanitize or limit the pathname parameters passed to the index.php file, creating an opportunity for malicious file inclusion attacks. The issue is classified as a local file inclusion vulnerability which can be exploited by an attacker who already has access to the system, making it particularly concerning for environments where local access might be compromised.
The technical implementation of this vulnerability involves the application's failure to properly validate or sanitize input parameters before using them in file operations. When user-controlled data is directly incorporated into file path constructions without adequate sanitization, attackers can manipulate the path to include unintended files. This flaw directly relates to CWE-22 which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal attacks. The vulnerability enables an attacker to potentially read sensitive files, execute arbitrary code, or gain unauthorized access to system resources that should remain protected. The impact is particularly severe because it allows for arbitrary file inclusion, which can lead to complete system compromise if combined with other attack vectors.
The operational impact of this vulnerability extends beyond simple data exposure, as it can enable attackers to escalate privileges and access sensitive system information. In a typical attack scenario, an adversary with local access could leverage this vulnerability to include system configuration files, credential files, or other sensitive data stored on the Nagios XI server. The vulnerability also poses risks to the integrity of the monitoring system itself, potentially allowing attackers to modify or corrupt critical monitoring data. Organizations using affected Nagios XI versions face significant risk of unauthorized access to their monitoring infrastructure, which could result in loss of visibility into their network operations and potential undetected compromise of other systems. This vulnerability aligns with ATT&CK technique T1059 which covers command and scripting interpreter, as attackers could potentially use the included files to execute malicious commands.
Mitigation strategies for this vulnerability require immediate patching of Nagios XI to version 5.8.5 or later, which addresses the improper pathname limitation issue through proper input validation and sanitization. Organizations should also implement network segmentation and access controls to limit local system access where possible, reducing the attack surface for local file inclusion exploits. Additional defensive measures include monitoring for unusual file access patterns, implementing proper file permissions, and conducting regular security assessments of the monitoring infrastructure. Security teams should also review and harden the configuration of Nagios XI installations, ensuring that unnecessary file access permissions are removed and that proper input validation is implemented across all web application components. Regular security updates and vulnerability management processes are essential to prevent similar issues from arising in other components of the monitoring infrastructure.