CVE-2013-1963 in ownCloud
Summary
by MITRE
The contacts application in ownCloud before 4.5.10 and 5.x before 5.0.5 does not properly check the ownership of contacts, which allows remote authenticated users to download arbitrary contacts via unspecified vectors.
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Analysis
by VulDB Data Team • 03/31/2025
The vulnerability described in CVE-2013-1963 represents a critical access control flaw within the contacts application of ownCloud software versions prior to 4.5.10 and 5.0.5. This issue stems from insufficient validation of contact ownership permissions, creating a scenario where authenticated users can exploit the system to access contacts belonging to other users. The vulnerability affects a widely used open source file sharing and synchronization platform that serves millions of users globally, making the potential impact substantial across both personal and enterprise deployments. The flaw exists in the application layer of the ownCloud ecosystem, specifically within the contact management functionality that handles user data sharing and access controls.
The technical implementation of this vulnerability lies in the improper validation mechanisms within the contacts application's permission checking system. When users interact with contact data through the ownCloud interface, the system should verify that the requesting user has legitimate authorization to access specific contact records. However, the vulnerability allows authenticated attackers to bypass these checks through unspecified vectors that likely involve manipulating API requests or direct database queries. This weakness enables unauthorized data access patterns that violate fundamental principles of data isolation and user privacy. The vulnerability aligns with CWE-284, which addresses improper access control, and represents a classic case of insufficient authorization checks in web applications. The flaw essentially allows privilege escalation through data access manipulation rather than traditional authentication bypass techniques.
The operational impact of this vulnerability extends beyond simple data exposure, as it enables potential data theft, privacy violations, and unauthorized information gathering across multiple user accounts. Attackers could systematically harvest contact information from other users, potentially building comprehensive address books that could be used for social engineering attacks, phishing campaigns, or identity theft. Organizations relying on ownCloud for business communications face significant risks, as the breach could expose sensitive contact data including email addresses, phone numbers, and personal identifiers. The vulnerability affects both individual users who might lose privacy of their personal contacts and enterprises that could experience data leakage from their employee contact databases. This type of information disclosure vulnerability often serves as a stepping stone for more sophisticated attacks, as contact information can be leveraged for credential stuffing, targeted attacks, or reconnaissance activities. The ATT&CK framework categorizes this under T1213, which covers data from information repositories, and represents a clear violation of data confidentiality principles.
Mitigation strategies for this vulnerability require immediate patching of affected ownCloud installations to versions 4.5.10 and 5.0.5 respectively, which contain the necessary authorization checks and permission validation fixes. System administrators should implement comprehensive access control reviews and consider additional security measures such as network segmentation, monitoring of unusual data access patterns, and enforcement of principle of least privilege. Organizations should conduct thorough audits of their ownCloud deployments to identify any custom configurations that might exacerbate the vulnerability. The fix likely involves strengthening the contact ownership verification mechanisms to ensure that all data access requests are properly authenticated and authorized. Additionally, implementing proper logging and alerting systems for unauthorized access attempts can help detect exploitation attempts and provide forensic evidence for incident response activities. Regular security assessments and penetration testing should be conducted to identify similar access control weaknesses in other applications within the organization's technology stack.