CVE-2021-4359 in Frontend File Manager Plugin
Summary
by MITRE • 06/07/2023
The Frontend File Manager plugin for WordPress is vulnerable to Unauthenticated Arbitrary Post Deletion in versions up to, and including, 18.2. This is due to lacking authentication protections and lacking a security nonce on the wpfm_delete_file AJAX action. This makes it possible for unauthenticated attackers to delete any posts and pages on the site.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 07/05/2023
The Frontend File Manager plugin for WordPress represents a critical security vulnerability that exposes WordPress sites to unauthorized deletion of content through the exploitation of insufficient authentication mechanisms. This vulnerability affects versions up to and including 18.2, making it a widespread concern for WordPress administrators who have not updated their installations. The flaw lies within the plugin's handling of the wpfm_delete_file AJAX action, which fails to implement proper authentication checks or security nonce validation. This omission creates a direct pathway for malicious actors to manipulate the plugin's functionality without requiring any valid user credentials or authorization. The vulnerability's classification aligns with CWE-863, which addresses "Incorrect Authorization" in software systems where access control mechanisms are improperly implemented or missing entirely. Attackers can exploit this weakness by crafting malicious requests that target the specific AJAX endpoint, thereby bypassing WordPress's standard authentication flow and gaining the ability to delete arbitrary posts and pages within the affected WordPress installation.
The operational impact of this vulnerability extends beyond simple content removal, as it fundamentally compromises the integrity and availability of WordPress sites. Unauthenticated attackers can systematically delete critical website content including blog posts, pages, media files, and other published materials without detection or resistance from the system. This capability enables a range of malicious activities including defacement of websites, disruption of business operations, and potential data loss that could severely impact organizations relying on their WordPress platforms for content management. The vulnerability's exploitation does not require advanced technical skills or insider knowledge, making it particularly dangerous as it can be leveraged by threat actors with minimal expertise. The absence of proper authorization checks means that even casual visitors to the website could potentially access this functionality, creating an attack surface that is both broad and easily exploitable. From an ATT&CK framework perspective, this vulnerability maps to the T1485 technique for "Data Destruction" and potentially T1078 for "Valid Accounts" if attackers can escalate privileges through other means after initial exploitation.
Mitigation strategies for this vulnerability must prioritize immediate plugin updates to versions that address the authentication and nonce validation issues. WordPress administrators should conduct thorough audits of their installed plugins to identify all instances of the Frontend File Manager plugin and ensure they are running patched versions. The recommended approach involves implementing proper security controls including mandatory authentication checks for all AJAX actions and enforcing strict nonce validation mechanisms. Organizations should also consider implementing additional monitoring and logging around AJAX endpoints to detect unusual activity patterns that might indicate exploitation attempts. Network-level protections such as web application firewalls can provide additional defense in depth by blocking suspicious requests targeting known vulnerable endpoints. The vulnerability highlights the importance of proper input validation and access control implementation in WordPress plugins, particularly those handling sensitive operations like content deletion. Security best practices dictate that all AJAX actions should require proper authentication and authorization checks, with nonce validation serving as an additional layer of protection against cross-site request forgery attacks. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other plugins and themes that may expose similar risks to unauthorized content manipulation.