CVE-2016-1505 in Radicale
Summary
by MITRE
The filesystem storage backend in Radicale before 1.1 on Windows allows remote attackers to read or write to arbitrary files via a crafted path, as demonstrated by /c:/file/ignore.
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Analysis
by VulDB Data Team • 07/06/2022
The vulnerability identified as CVE-2016-1505 represents a critical path traversal flaw within the Radicale web server filesystem storage backend specifically affecting versions prior to 1.1 on Windows operating systems. This vulnerability stems from inadequate input validation and path handling mechanisms that fail to properly sanitize user-supplied paths before processing them within the filesystem context. The flaw enables remote attackers to manipulate file access patterns through carefully crafted URLs that contain Windows-specific path references, allowing unauthorized read and write operations on arbitrary files within the system.
The technical implementation of this vulnerability exploits the fundamental design weakness in how Radicale processes filesystem paths on Windows platforms. When a user submits a request containing a path such as /c:/file/ignore, the application fails to properly validate or normalize the path structure, leading to a situation where the system interprets the crafted path as a legitimate filesystem access request. This allows attackers to bypass normal access controls and potentially access sensitive system files, configuration data, or even modify critical application files. The vulnerability specifically targets the Windows filesystem handling logic where absolute paths starting with drive letters are not properly restricted or sanitized.
From an operational impact perspective, this vulnerability presents a severe security risk that can lead to complete system compromise when exploited by remote attackers. The ability to read arbitrary files means that attackers can potentially access sensitive information such as configuration files containing database credentials, user authentication data, or application secrets. Write access capabilities further amplify the threat, enabling attackers to modify application files, inject malicious code, or corrupt system data. The vulnerability is particularly dangerous in environments where Radicale serves as a calendar or contact management service, as it could lead to unauthorized access to personal or corporate data. This flaw aligns with CWE-22 Path Traversal vulnerabilities and can be mapped to ATT&CK technique T1059 Command and Scripting Interpreter and T1074 Data Staged, as attackers can both extract and manipulate data through this pathway.
The mitigation strategies for this vulnerability primarily focus on upgrading to Radicale version 1.1 or later where the path traversal protections have been implemented. System administrators should also implement network-level restrictions to limit access to the Radicale service to trusted networks only, and consider implementing additional input validation at proxy or firewall levels. Regular security audits should verify that no unauthorized file access permissions exist for the Radicale service account, and implementing principle of least privilege access controls can help limit the damage if exploitation occurs. Organizations should also monitor for any unauthorized file modifications or access patterns that could indicate exploitation attempts, particularly looking for unusual file access requests or modifications to system files. The vulnerability demonstrates the importance of proper input sanitization and path validation, particularly when dealing with cross-platform applications that must handle different filesystem conventions and security models.