CVE-2020-28910 in Nagios
Summary
by MITRE • 05/24/2021
Creation of a Temporary Directory with Insecure Permissions in Nagios XI 5.7.5 and earlier allows for Privilege Escalation via creation of symlinks, which are mishandled in getprofile.sh.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 05/27/2021
The vulnerability identified as CVE-2020-28910 affects Nagios XI versions 5.7.5 and earlier, presenting a critical security flaw that enables privilege escalation through insecure temporary directory creation. This issue stems from the improper handling of temporary file permissions during the execution of getprofile.sh script, creating a pathway for malicious actors to manipulate system privileges. The vulnerability manifests when the system creates temporary directories without adequate permission controls, allowing unauthorized users to establish symbolic links that can be exploited to gain elevated privileges. This flaw directly violates security principles by failing to implement proper access controls and privilege separation mechanisms that are fundamental to secure system design.
The technical implementation of this vulnerability occurs within the getprofile.sh script which is responsible for profile management within the Nagios XI environment. When the script executes, it creates temporary directories that are susceptible to insecure permissions, typically allowing world-writable access or improper ownership settings. Attackers can exploit this by creating symbolic links within these temporary directories that point to sensitive system files or configuration resources. The mismanagement occurs during the symlink resolution process where the system does not properly validate or sanitize the symbolic link targets, allowing arbitrary file access and modification. This represents a classic case of insecure temporary file handling that aligns with CWE-377, which addresses the creation of temporary files with insecure permissions.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data integrity breaches. An attacker with basic user access can leverage this vulnerability to elevate their privileges to root or administrative levels, thereby gaining complete control over the Nagios XI server. This escalation enables unauthorized access to monitoring data, configuration files, and potentially other systems within the network that rely on the monitoring infrastructure. The vulnerability's exploitation can lead to persistent backdoors, data exfiltration, and disruption of critical monitoring services that organizations depend upon for operational security. The impact is particularly severe in enterprise environments where Nagios XI is used for comprehensive system monitoring and security orchestration.
Mitigation strategies for CVE-2020-28910 require immediate implementation of both patch management and configuration hardening measures. Organizations should upgrade to Nagios XI versions that have addressed this vulnerability, as the official patches typically include proper permission controls for temporary directory creation and enhanced symlink validation. System administrators should also implement immediate remediation by reviewing and correcting temporary directory permissions, ensuring that any temporary files created during script execution have restrictive permissions and are owned by appropriate system users. The implementation should follow security best practices such as the principle of least privilege and proper file system access controls, aligning with ATT&CK technique T1078 which addresses valid accounts and privilege escalation. Additionally, regular security audits should be conducted to identify and remediate similar insecure temporary file handling patterns in other applications and system components.