CVE-2022-2278 in Featured Image from URL Plugin
Summary
by MITRE • 08/01/2022
The Featured Image from URL (FIFU) WordPress plugin before 4.0.1 does not validate, sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks when the unfiltered_html capability is disallowed (for example in multisite setup)
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Analysis
by VulDB Data Team • 08/01/2022
The featured image from url plugin for wordpress represents a critical security vulnerability that affects versions prior to 4.0.1, creating a pathway for stored cross-site scripting attacks within wordpress environments. This vulnerability specifically targets the plugin's handling of user settings and configuration parameters, where insufficient input validation and sanitization processes leave the system exposed to malicious code injection. The flaw manifests when high-privilege users with administrative capabilities attempt to manipulate plugin settings, particularly in multisite configurations where the unfiltered_html capability has been restricted to prevent direct html injection. The vulnerability falls under the category of CWE-79 - Cross-site Scripting, which is a fundamental weakness in web applications that allows attackers to inject client-side scripts into web pages viewed by other users. The specific technical implementation flaw involves the plugin's failure to properly escape and validate user-supplied data before it is stored in the database and subsequently rendered on web pages. This oversight creates a persistent threat where malicious scripts can be executed whenever affected pages are loaded, potentially compromising user sessions and enabling unauthorized access to sensitive data.
The operational impact of this vulnerability extends beyond simple script execution, as it can be exploited to perform more sophisticated attacks within the wordpress ecosystem. In multisite environments where the unfiltered_html capability is restricted, administrators and other high-privilege users still retain the ability to manipulate plugin settings through the wp-admin interface. When these settings are improperly sanitized, the malicious code becomes permanently stored within the plugin's configuration data, making it persistent across page loads and user sessions. The vulnerability is particularly concerning because it leverages the trust relationship between the administrator and the plugin, allowing attackers to execute scripts in the context of the victim's browser session. This could potentially lead to session hijacking, privilege escalation, or the redirection of users to malicious sites. The attack vector is relatively straightforward since it requires only that an attacker possess administrative privileges or the ability to manipulate plugin settings, which are often granted to trusted users within wordpress installations. The stored nature of the vulnerability means that the malicious payload remains active until explicitly removed by an administrator, creating a persistent threat that can affect multiple users over extended periods.
Security mitigations for this vulnerability must address both the immediate code-level fixes and broader administrative controls to prevent exploitation. The primary solution involves implementing proper input validation and output escaping mechanisms within the plugin's settings handling code, ensuring that all user-supplied data undergoes sanitization before being stored or rendered. This includes applying wp_kses() or similar functions to sanitize html content, implementing strict data type validation, and ensuring that all plugin settings are properly escaped when displayed in admin interfaces. Organizations should also consider implementing role-based access controls that limit the ability of users to modify plugin settings, particularly in environments where the unfiltered_html capability has been restricted. The vulnerability demonstrates the importance of following secure coding practices as outlined in the OWASP Top 10 and the ATT&CK framework, where the persistence of malicious code through stored XSS attacks represents a significant threat vector that requires comprehensive defense measures. Administrators should also implement regular security audits of installed plugins, ensuring that all third-party components are kept up-to-date with the latest security patches. Additionally, monitoring for unusual plugin configuration changes and implementing web application firewalls can provide additional layers of protection against exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper input validation and output escaping in web applications, particularly when dealing with user-supplied data in privileged contexts where the potential for damage is significantly elevated.