CVE-2020-29454 in Umbraco
Summary
by MITRE • 12/02/2020
Editors/LogViewerController.cs in Umbraco through 8.9.1 allows a user to visit a logviewer endpoint even if they lack Applications.Settings access.
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Analysis
by VulDB Data Team • 12/11/2020
The vulnerability identified as CVE-2020-29454 affects Umbraco versions through 8.9.1 and resides within the Editors/LogViewerController.cs file. This represents a critical access control flaw that undermines the application's security model by allowing unauthorized users to access sensitive log viewer functionality without proper authorization. The issue stems from insufficient permission checks within the log viewer controller implementation, creating a pathway for privilege escalation and information disclosure.
The technical flaw manifests as a missing authorization check in the LogViewerController.cs file where the application fails to validate whether the authenticated user possesses the necessary Applications.Settings permissions before granting access to log viewing endpoints. This misconfiguration creates a direct bypass of Umbraco's intended access control mechanisms, allowing any authenticated user to potentially access system logs, error messages, and other sensitive operational data that should only be available to users with elevated administrative privileges. The vulnerability operates at the application logic level and can be categorized under CWE-284 Access Control Issues, specifically involving insufficient access control checks.
The operational impact of this vulnerability extends beyond simple information disclosure, as system logs often contain sensitive data including user credentials, system configurations, database connection strings, and detailed error information that could aid attackers in subsequent exploitation attempts. An attacker with basic user credentials could leverage this vulnerability to gather intelligence about the system architecture, identify potential weaknesses in other components, and potentially discover additional vulnerabilities through log content analysis. This vulnerability directly violates the principle of least privilege and can be mapped to ATT&CK technique T1213 Data from Information Repositories, as it provides unauthorized access to system information repositories.
Organizations utilizing affected Umbraco versions should immediately implement mitigations including applying the available patches from Umbraco, implementing additional authorization layers at the web server level, and conducting thorough access control reviews. The vulnerability can be addressed through proper code auditing to ensure all controller endpoints validate appropriate permissions before execution, implementing role-based access control mechanisms, and establishing monitoring for unauthorized log access attempts. Security teams should also consider implementing network segmentation and additional logging to detect potential exploitation attempts. This vulnerability highlights the critical importance of proper access control implementation and demonstrates how seemingly minor authorization gaps can create significant security risks in content management systems.