CVE-2012-5336 in ownCloud
Summary
by MITRE
lib/base.php in ownCloud before 4.0.8 does not properly validate the user_id session variable, which allows remote authenticated users to read arbitrary files via vectors related to WebDAV.
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Analysis
by VulDB Data Team • 03/31/2025
The vulnerability identified as CVE-2012-5336 affects ownCloud versions prior to 4.0.8, specifically within the lib/base.php file where insufficient validation of the user_id session variable creates a critical security flaw. This issue enables authenticated remote attackers to exploit WebDAV functionality to read arbitrary files from the system, representing a significant authorization bypass vulnerability that undermines the application's core security model. The flaw exists in the session management mechanism where the application fails to properly sanitize or validate the user_id parameter that is typically passed through session cookies or WebDAV requests.
The technical implementation of this vulnerability stems from improper input validation within the WebDAV interface implementation. When users authenticate to the ownCloud system, session variables including user_id are established to maintain user context across requests. However, the lib/base.php component fails to adequately validate these session variables before processing file operations, allowing maliciously crafted requests to manipulate the user_id value and gain access to files beyond the authenticated user's intended scope. This type of vulnerability aligns with CWE-20, which covers improper input validation, and represents a classic case of insecure direct object reference where the application directly uses user-supplied input to determine which resources to access.
The operational impact of this vulnerability is severe as it allows authenticated attackers to potentially access sensitive files that belong to other users within the same ownCloud instance. Attackers can leverage this weakness to read configuration files, user data, system logs, or other sensitive information that should remain protected within the application's access control boundaries. The WebDAV protocol support in ownCloud provides an additional attack surface where these session manipulation techniques can be effectively exploited. This vulnerability essentially allows privilege escalation within the application's user access control model, enabling unauthorized data access that could lead to data breaches or further system compromise.
Mitigation strategies for this vulnerability require immediate patching of ownCloud installations to version 4.0.8 or later where the session validation has been properly implemented. Organizations should also conduct thorough security assessments of their ownCloud deployments to identify any potential exploitation attempts or unauthorized access patterns. Network monitoring should be enhanced to detect unusual WebDAV activity patterns that might indicate exploitation attempts. Additionally, implementing proper access controls and ensuring that all session management components properly validate user identifiers can prevent similar issues. This vulnerability demonstrates the importance of proper session validation and input sanitization, aligning with ATT&CK technique T1566 which covers credential access through exploitation of application vulnerabilities. Security teams should also consider implementing network segmentation and access controls to limit the potential impact of such vulnerabilities, ensuring that even if one user account is compromised, the attacker cannot easily escalate privileges or access other users' data.