CVE-2015-6500 in Server
Summary
by MITRE
Directory traversal vulnerability in ownCloud Server before 8.0.6 and 8.1.x before 8.1.1 allows remote authenticated users to list directory contents and possibly cause a denial of service (CPU consumption) via a .. (dot dot) in the dir parameter to index.php/apps/files/ajax/scan.php.
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Analysis
by VulDB Data Team • 04/01/2025
The vulnerability identified as CVE-2015-6500 represents a critical directory traversal flaw within ownCloud Server versions prior to 8.0.6 and 8.1.x before 8.1.1. This weakness resides in the file scanning functionality exposed through the index.php/apps/files/ajax/scan.php endpoint, which processes directory parameters without adequate validation. The vulnerability specifically affects authenticated users who can manipulate the dir parameter to include directory traversal sequences using the .. (dot dot) notation. This flaw allows attackers to bypass normal access controls and gain unauthorized access to directory structures beyond the intended scope of the application's file management system.
The technical implementation of this vulnerability stems from insufficient input sanitization and path validation within the file scanning component of ownCloud's web interface. When the application processes the dir parameter through the ajax/scan.php endpoint, it fails to properly validate or sanitize user-supplied directory paths, enabling attackers to craft malicious requests that traverse parent directories. This weakness directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as directory traversal or path traversal attacks. The vulnerability's exploitation requires only authenticated access, making it particularly dangerous as it can be leveraged by users who have legitimate credentials but should not have access to restricted directories.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable denial of service conditions through excessive CPU consumption. Attackers can craft requests that cause the application to process directory structures recursively, leading to significant computational overhead and resource exhaustion. This CPU consumption can result in system performance degradation or complete service unavailability, particularly when scanning large directory hierarchies or when the vulnerability is exploited repeatedly. The vulnerability's potential for DoS exploitation aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion, and represents a significant risk to service availability in enterprise environments where ownCloud serves as a primary file sharing solution.
Organizations affected by CVE-2015-6500 should immediately implement the vendor-provided patches for ownCloud Server versions 8.0.6 and 8.1.1, which address the directory traversal flaw through proper input validation and path sanitization. The remediation process should include comprehensive testing of the updated system to ensure that file scanning functionality operates correctly while maintaining proper access controls. Security administrators should also implement monitoring for suspicious directory traversal patterns in web server logs and consider implementing additional access controls or network segmentation to limit the potential impact of authenticated attacks. The vulnerability demonstrates the importance of input validation in web applications and highlights the need for regular security updates to protect against known exploits that could compromise system integrity and availability.