CVE-2018-15711 in Nagios XI
Summary
by MITRE
Nagios XI 5.5.6 allows remote authenticated attackers to reset and regenerate the API key of more privileged users. The attacker can then use the new API key to execute API calls at elevated privileges.
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Analysis
by VulDB Data Team • 04/12/2020
Nagios XI version 5.5.6 contains a critical privilege escalation vulnerability that enables authenticated attackers to manipulate API key permissions and execute elevated operations. This vulnerability resides within the application's authentication and authorization mechanisms, specifically affecting the API key management functionality. The flaw allows an attacker with valid credentials to perform unauthorized actions that should be restricted to administrators or users with higher privileges. The vulnerability impacts the core security model of the application by undermining the principle of least privilege, where users should only have access to resources necessary for their specific roles.
The technical implementation of this vulnerability stems from insufficient input validation and access control checks within the API key regeneration process. When authenticated users attempt to reset API keys for other accounts, the application fails to properly verify whether the requesting user has adequate permissions to modify the target user's credentials. This weakness creates a path for privilege escalation where a lower-privileged user can effectively impersonate higher-privileged accounts by obtaining and using regenerated API keys. The vulnerability manifests through the application's API endpoints that handle key management operations without proper authorization verification. According to the CWE database, this corresponds to CWE-285: Improper Authorization, which specifically addresses insufficient checks for proper authorization.
The operational impact of this vulnerability extends beyond simple credential theft, as it enables attackers to execute arbitrary API calls with elevated privileges. This capability allows threat actors to perform actions such as modifying system configurations, accessing sensitive data, creating or deleting user accounts, and potentially gaining deeper system access. The attack vector requires only authentication credentials, making it particularly dangerous as it can be exploited by users who have legitimate access to the system but lack administrative privileges. This vulnerability directly maps to ATT&CK technique T1078.004: Valid Accounts - Cloud Accounts, where attackers leverage legitimate credentials to gain elevated access within cloud environments. The implications are severe as it essentially allows privilege escalation without requiring additional attack vectors or exploiting other vulnerabilities.
Organizations using Nagios XI 5.5.6 should immediately implement mitigations including applying the vendor-provided security patches, implementing additional access controls, and monitoring API key usage patterns for unusual activities. The recommended approach involves updating to a patched version of Nagios XI that addresses the authorization flaw. Additionally, administrators should review and restrict API key permissions, implement logging of key regeneration events, and establish monitoring procedures to detect unauthorized key modifications. The vulnerability demonstrates the critical importance of proper authorization checking in web applications and highlights the need for regular security assessments of authentication mechanisms. Organizations should also consider implementing multi-factor authentication and role-based access controls to further reduce the impact of such vulnerabilities. The security community should treat this as a high-priority issue requiring immediate attention across all systems utilizing affected versions of Nagios XI.