CVE-2023-6251 in Checkmk
Summary
by MITRE • 11/24/2023
Cross-site Request Forgery (CSRF) in Checkmk < 2.2.0p15, < 2.1.0p37, <= 2.0.0p39 allow an authenticated attacker to delete user-messages for individual users.
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Analysis
by VulDB Data Team • 04/21/2025
The vulnerability identified as CVE-2023-6251 represents a critical cross-site request forgery weakness affecting Checkmk monitoring software across multiple version ranges. This flaw permits authenticated attackers to manipulate the system's message handling functionality, specifically targeting the deletion of user messages. The vulnerability exists within the web application's request processing mechanism, where proper validation of request origins and authenticity tokens is insufficiently implemented. Attackers can exploit this weakness to execute unauthorized actions on behalf of legitimate users, potentially compromising the integrity of user communications and system access controls.
The technical implementation of this CSRF vulnerability stems from the absence of proper anti-CSRF token validation within the message deletion endpoints. When users navigate to affected Checkmk installations, the application fails to adequately verify that requests originating from message deletion functions are genuinely authorized by the authenticated user. This weakness allows attackers to craft malicious requests that appear legitimate to the server, exploiting the trust relationship between the web application and its users. The vulnerability is particularly concerning as it affects multiple major release branches, indicating a systemic flaw in the application's security architecture rather than an isolated incident.
The operational impact of this vulnerability extends beyond simple message deletion, potentially enabling attackers to disrupt user communications, manipulate access controls, or escalate privileges within the monitoring environment. An authenticated attacker can leverage this flaw to remove critical alert notifications or user-specific messages, potentially leading to missed security incidents or operational disruptions. The vulnerability affects the core functionality of user management and communication within Checkmk, which could compromise the overall security posture of monitoring systems that rely on timely message delivery. This weakness particularly impacts organizations that depend on Checkmk for critical infrastructure monitoring, where message integrity and availability are essential for operational continuity.
Organizations should immediately implement mitigations including the deployment of proper anti-CSRF token mechanisms, enforcement of strict origin validation for all critical endpoints, and implementation of additional authentication layers for sensitive operations. The vulnerability aligns with CWE-352, which specifically addresses cross-site request forgery flaws in web applications, and maps to ATT&CK technique T1566.001 for the initial access vector through web application exploitation. Security teams should also consider implementing web application firewalls, monitoring for suspicious request patterns, and conducting comprehensive penetration testing to identify potential exploitation vectors. Regular updates to Checkmk installations should be prioritized, with particular attention to version 2.2.0p15, 2.1.0p37, and 2.0.0p39 or later releases that contain the necessary security patches to address this vulnerability.