CVE-2020-28900 in Fusion
Summary
by MITRE • 05/24/2021
Insufficient Verification of Data Authenticity in Nagios Fusion 4.1.8 and earlier and Nagios XI 5.7.5 and earlier allows for Escalation of Privileges or Code Execution as root via vectors related to an untrusted update package to upgrade_to_latest.sh.
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Analysis
by VulDB Data Team • 05/27/2021
The vulnerability identified as CVE-2020-28900 represents a critical security flaw in Nagios Fusion and Nagios XI monitoring platforms affecting versions up to 4.1.8 and 5.7.5 respectively. This issue stems from insufficient verification of data authenticity during the update process, creating a pathway for malicious actors to escalate privileges or execute arbitrary code with root-level permissions. The vulnerability specifically targets the upgrade_to_latest.sh script which handles update package installations, making it a prime target for attackers seeking system compromise.
The technical flaw manifests in the lack of proper digital signature verification and authenticity checks when processing update packages. Attackers can exploit this weakness by crafting malicious update packages that appear legitimate to the system's verification mechanisms. When the upgrade_to_latest.sh script processes these forged packages, it executes the malicious code with root privileges, effectively bypassing all standard security controls and access restrictions. This vulnerability aligns with CWE-347, which addresses the lack of proper validation of digital signatures or other forms of cryptographic authentication, and represents a classic example of a supply chain attack vector.
The operational impact of this vulnerability is severe and multifaceted, potentially allowing attackers to gain complete system control, modify critical monitoring configurations, and establish persistent backdoors within network infrastructure. Organizations using affected Nagios versions face significant risk as the vulnerability can be exploited remotely without requiring prior authentication, making it particularly dangerous in enterprise environments where monitoring systems serve as critical infrastructure components. The privilege escalation aspect means that even if an attacker initially gains access through other means, they can leverage this vulnerability to achieve full system compromise and maintain persistent access.
Mitigation strategies for CVE-2020-28900 should prioritize immediate patching of affected systems to the latest available versions that address the authentication verification flaw. Organizations should implement network segmentation to limit access to monitoring systems and establish strict firewall rules preventing unauthorized update package transfers. Additionally, security teams should conduct comprehensive audits of update processes and implement automated monitoring for suspicious package installations. The remediation approach should align with ATT&CK framework tactics related to privilege escalation and execution, ensuring that defensive measures address both the immediate vulnerability and broader attack surface considerations. Regular security assessments and vulnerability scanning should be implemented to detect similar weaknesses in other system components and maintain ongoing protection against evolving threats.