CVE-2019-12464 in LibreNMS
Summary
by MITRE
An issue was discovered in LibreNMS 1.50.1. An authenticated user can perform a directory traversal attack against the /pdf.php file with a partial filename in the report parameter, to cause local file inclusion resulting in code execution.
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Analysis
by VulDB Data Team • 12/18/2023
The vulnerability identified as CVE-2019-12464 resides within the LibreNMS network monitoring platform version 1.50.1, representing a critical security flaw that enables authenticated users to execute arbitrary code through a directory traversal attack. This vulnerability specifically targets the /pdf.php endpoint where the report parameter is processed without adequate input validation, creating a pathway for attackers to manipulate file paths and access sensitive system resources. The flaw allows an attacker with valid credentials to bypass normal access controls and potentially gain unauthorized access to the underlying operating system.
The technical implementation of this vulnerability stems from improper input sanitization within the LibreNMS application codebase, where user-supplied data from the report parameter is directly incorporated into file system operations without sufficient validation or sanitization measures. This weakness enables attackers to craft malicious payloads that exploit the directory traversal mechanism, allowing them to navigate through the file system hierarchy and access files that should remain restricted. The vulnerability operates under CWE-22 which categorizes directory traversal attacks as a fundamental flaw in input validation, where insufficient restrictions on user-provided input enable attackers to access files outside the intended directory structure. The flaw essentially allows attackers to construct file paths that include directory traversal sequences such as ../ or ..\ which can be used to access system files, configuration data, or even execute arbitrary code on the server.
The operational impact of this vulnerability extends beyond simple data theft, as it provides attackers with the capability to execute arbitrary code on the affected server, potentially leading to complete system compromise. An authenticated user with access to the LibreNMS platform can leverage this vulnerability to access sensitive system information, modify or delete critical files, and potentially establish persistent backdoors within the network monitoring infrastructure. This poses significant risks to network security operations since LibreNMS systems often contain sensitive network topology information, device credentials, and monitoring data that could be exploited for further attacks within the network. The attack vector is particularly concerning because it requires only authentication credentials, which are often less protected than network-level access controls, making the exploitation more likely in environments where user access is not strictly controlled.
Security mitigations for CVE-2019-12464 should include immediate patching of the LibreNMS platform to version 1.50.2 or later, which contains the necessary fixes for the directory traversal vulnerability. Organizations should also implement additional security controls such as input validation and sanitization measures at the application level, ensuring that all user-provided parameters are properly validated before being processed. Network segmentation and access controls should be strengthened to limit the impact of potential exploitation, and monitoring systems should be enhanced to detect unusual file access patterns that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1059 which covers execution through command and scripting interpreters, and T1083 which covers file and directory discovery, indicating that exploitation efforts would likely involve both code execution and reconnaissance activities. Additionally, implementing proper principle of least privilege access controls and regular security audits can help reduce the overall risk exposure associated with this vulnerability.