CVE-2020-28644 in ownCloud
Summary
by MITRE • 02/10/2021
The CSRF (Cross Site Request Forgery) token check was improperly implemented on cookie authenticated requests against some ocs API endpoints. This affects ownCloud/core version < 10.6.
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Analysis
by VulDB Data Team • 02/27/2021
The vulnerability described in CVE-2020-28644 represents a critical weakness in the cross site request forgery protection mechanisms within the ownCloud/core platform. This issue specifically impacts versions prior to 10.6 where the implementation of CSRF token validation fails to properly secure cookie-authenticated API endpoints. The flaw lies in the improper enforcement of CSRF protection measures, creating a pathway for malicious actors to exploit the authentication system through crafted requests that appear legitimate to the server.
The technical implementation flaw stems from the inadequate validation of CSRF tokens when processing requests that rely on cookie-based authentication. In properly secured systems, CSRF tokens should be validated against each request to ensure that the request originates from an authenticated user session rather than being submitted through a malicious third-party site. However, in this vulnerability, the validation process fails to adequately verify the token's authenticity when cookie authentication is used, effectively bypassing the protection mechanism that should prevent unauthorized actions from being executed on behalf of authenticated users.
The operational impact of this vulnerability extends beyond simple data exposure, as it enables attackers to perform unauthorized actions within the context of authenticated user sessions. This includes potential file manipulation, data deletion, user account modifications, and other administrative functions that could compromise the integrity and confidentiality of the ownCloud deployment. The vulnerability is particularly dangerous because it affects API endpoints that are commonly used for administrative tasks, making it a prime target for attackers seeking to escalate privileges or cause system-wide damage.
Organizations running ownCloud/core versions prior to 10.6 face significant risk from this vulnerability, as it can be exploited through various attack vectors including phishing campaigns, compromised user sessions, or by leveraging existing access to the system. The vulnerability directly relates to CWE-352, which describes Cross-Site Request Forgery, and aligns with ATT&CK technique T1078.004 for Valid Accounts and T1566.001 for Phishing, as attackers can leverage authenticated sessions to execute malicious requests without requiring additional credentials. The improper implementation creates a persistent security gap that allows for automated exploitation and can result in substantial data loss or system compromise.
The recommended mitigation strategy involves immediate upgrading to ownCloud/core version 10.6 or later, where the CSRF token validation has been properly implemented. Organizations should also implement additional security measures including monitoring for unusual API activity patterns, enforcing strict access controls for administrative endpoints, and conducting regular security assessments of their cloud infrastructure. Network segmentation and web application firewalls can provide additional layers of protection while the primary upgrade addresses the core vulnerability. Security teams should also review their incident response procedures to ensure readiness for potential exploitation attempts and maintain comprehensive logging of all API endpoint interactions for forensic analysis purposes.