CVE-2018-21020 in Web
Summary
by MITRE
In very rare cases, a PHP type juggling vulnerability in centreonAuth.class.php in Centreon Web before 2.8.27 allows attackers to bypass authentication mechanisms in place.
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Analysis
by VulDB Data Team • 08/27/2024
The vulnerability identified as CVE-2018-21020 represents a critical PHP type juggling flaw within the authentication system of Centreon Web versions prior to 2.8.27. This issue manifests in extremely rare circumstances where attackers can exploit the inherent weaknesses in PHP's type coercion mechanisms to bypass authentication controls. The vulnerability specifically resides in the centreonAuth.class.php file, which serves as the core authentication module for the Centreon web interface. Centreon Web is a widely deployed network monitoring and management platform that provides comprehensive IT infrastructure monitoring capabilities, making this authentication bypass particularly dangerous for organizations relying on its security controls.
The technical exploitation of this vulnerability leverages PHP's type juggling behavior, where the language automatically converts variables between different data types without explicit casting. In this specific case, the authentication logic in centreonAuth.class.php fails to properly validate user credentials through strict type checking, allowing attackers to craft malicious input that exploits the implicit type conversion. When PHP encounters certain input patterns, it performs automatic type coercion that can result in unexpected behavior, particularly when comparing user-provided data with expected authentication parameters. This creates a scenario where an attacker can manipulate input to match authentication checks without possessing valid credentials, effectively bypassing the authentication mechanism entirely. The vulnerability aligns with CWE-707, which addresses improper use of potentially dangerous APIs, and more specifically with CWE-501, concerning trust violations in authentication mechanisms.
The operational impact of this vulnerability extends beyond simple unauthorized access, as Centreon Web systems typically serve as central monitoring points for critical IT infrastructure. Organizations utilizing affected versions could face complete compromise of their monitoring systems, potentially allowing attackers to gain visibility into network operations, disable monitoring alerts, or manipulate critical infrastructure data. The authentication bypass could enable lateral movement within networks where Centreon is deployed as part of security monitoring infrastructure. Attackers might also exploit this vulnerability to establish persistent access points or to hide their activities from monitoring systems. This issue particularly affects enterprise environments where Centreon is used for security operations center (SOC) monitoring, making the potential damage significantly greater than in typical monitoring deployments.
Organizations should prioritize immediate remediation by upgrading to Centreon Web version 2.8.27 or later, which includes proper input validation and type checking mechanisms. Security teams should implement network segmentation and monitoring to detect potential exploitation attempts, particularly focusing on unusual authentication patterns or repeated login attempts from suspicious sources. The mitigation strategy should also include reviewing and hardening authentication configurations, implementing multi-factor authentication where possible, and conducting thorough security assessments of the monitoring infrastructure. This vulnerability demonstrates the importance of strict input validation in authentication systems and highlights the need for security-conscious development practices that avoid relying on implicit type conversions in security-critical code paths. The ATT&CK framework categorizes this as a privilege escalation technique through authentication bypass, emphasizing the need for robust access control measures and regular security updates to prevent exploitation of such vulnerabilities.