CVE-2020-35943 in NextGEN Gallery
Summary
by MITRE • 02/10/2021
A Cross-Site Request Forgery (CSRF) issue in the NextGEN Gallery plugin before 3.5.0 for WordPress allows File Upload. (It is possible to bypass CSRF protection by simply not including a nonce parameter.)
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Analysis
by VulDB Data Team • 02/27/2021
The vulnerability identified as CVE-2020-35943 represents a critical Cross-Site Request Forgery weakness in the NextGEN Gallery plugin for WordPress systems. This issue affects versions prior to 3.5.0 and fundamentally undermines the security mechanisms designed to protect against unauthorized actions executed on behalf of authenticated users. The vulnerability stems from the plugin's failure to properly validate CSRF tokens during file upload operations, creating a pathway for malicious actors to exploit the system's trust in legitimate user sessions.
The technical flaw manifests in the plugin's handling of file upload requests where the CSRF protection mechanism can be bypassed by simply omitting the required nonce parameter. This design oversight allows attackers to craft malicious requests that appear to originate from authenticated users, effectively circumventing the intended security controls. The vulnerability operates at the application layer and specifically targets the file upload functionality within the NextGEN Gallery plugin, which is a widely used component for managing and displaying media content on WordPress websites. The absence of proper nonce validation during the file upload process creates a direct vector for privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple unauthorized file uploads, potentially enabling attackers to execute arbitrary code on affected systems through malicious file uploads. When combined with other exploitation techniques, this CSRF vulnerability could allow attackers to gain persistent access to compromised WordPress installations, leading to complete system compromise. The attack surface is particularly concerning given that NextGEN Gallery is a popular plugin with widespread adoption across numerous WordPress deployments, meaning that a large number of websites could be vulnerable to this specific CSRF bypass mechanism. The vulnerability also aligns with attack patterns documented in the MITRE ATT&CK framework under the T1059 category for command and script injection, as malicious file uploads could contain executable payloads.
Security mitigations for CVE-2020-35943 require immediate patching of the NextGEN Gallery plugin to version 3.5.0 or later, where the CSRF protection mechanisms have been properly implemented. Organizations should also implement additional security controls including web application firewalls that can detect and block suspicious file upload patterns, monitoring of unusual upload activities, and regular security audits of installed plugins. The vulnerability demonstrates the critical importance of proper input validation and CSRF token implementation as outlined in CWE-352, which specifically addresses Cross-Site Request Forgery weaknesses in software applications. System administrators should also consider implementing additional layers of security including strict file type validation, upload size restrictions, and sandboxed execution environments for uploaded content to minimize potential damage from successful exploitation attempts.