CVE-2021-39213 in GLPI
Summary
by MITRE • 09/16/2021
GLPI is a free Asset and IT management software package. Starting in version 9.1 and prior to version 9.5.6, GLPI with API Rest enabled is vulnerable to API bypass with custom header injection. This issue is fixed in version 9.5.6. One may disable API Rest as a workaround.
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Analysis
by VulDB Data Team • 09/19/2021
The vulnerability identified as CVE-2021-39213 affects GLPI, a widely-used open-source asset and IT management software package that serves organizations in tracking hardware, software, and IT resources. This security flaw specifically targets installations where the REST API functionality has been enabled, creating a significant risk for organizations that rely on GLPI for critical infrastructure management. The vulnerability exists in versions 9.1 through 9.5.5, making it a long-standing issue that affected numerous deployments across different organizational environments. The flaw allows for unauthorized access to the system through a sophisticated bypass mechanism that exploits the API's handling of custom headers, potentially enabling attackers to gain elevated privileges or access sensitive data without proper authentication.
The technical nature of this vulnerability stems from improper validation of custom headers within the GLPI REST API implementation. When API requests are processed, the system fails to properly sanitize or validate custom header inputs, allowing attackers to inject malicious headers that can manipulate the API's authentication and authorization flow. This header injection technique enables unauthorized access to system resources and potentially allows attackers to execute administrative functions through the API interface. The vulnerability operates at the application layer and specifically targets the API gateway component of GLPI, where custom header parameters are processed without adequate input validation controls. This flaw aligns with CWE-20, which describes improper input validation, and represents a classic case of insecure API design where header manipulation can be exploited to bypass security controls.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it can enable attackers to perform a wide range of malicious activities within the compromised GLPI environment. Organizations may experience data breaches, unauthorized modifications to asset records, and potential privilege escalation that could lead to complete system compromise. The vulnerability affects the integrity and confidentiality of the entire IT asset management system, potentially exposing sensitive information about hardware inventory, software licenses, and user access rights. Attackers could leverage this vulnerability to manipulate asset tracking data, disrupt IT operations, or establish persistent access points within the organization's infrastructure. The impact is particularly severe for organizations that rely heavily on GLPI for critical IT management functions, as the compromise could affect business continuity and compliance requirements.
Organizations can mitigate this vulnerability by upgrading to GLPI version 9.5.6 or later, which includes proper input validation and header sanitization mechanisms that address the root cause of the issue. The recommended approach involves implementing a comprehensive patch management strategy to ensure all GLPI installations are updated to the secure version. As an alternative workaround, administrators can disable the REST API functionality entirely, though this may impact legitimate use cases that depend on API integration. Security teams should also implement network-level monitoring to detect suspicious header injection patterns and establish proper access controls for API endpoints. The mitigation strategy should align with industry best practices for API security and application hardening, incorporating principles from the OWASP API Security Top 10 framework. Organizations should conduct thorough testing of the updated version to ensure compatibility with existing integrations while verifying that the vulnerability has been properly resolved through proper security validation procedures.