CVE-2023-4811 in File Upload Plugin
Summary
by MITRE • 10/25/2023
The WordPress File Upload WordPress plugin before 4.23.3 does not sanitise and escape some of its settings, which could allow high privilege users such as contributors to perform Stored Cross-Site Scripting attacks.
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Analysis
by VulDB Data Team • 11/03/2023
The vulnerability identified as CVE-2023-4811 affects the WordPress File Upload plugin version 4.23.2 and earlier, presenting a critical security risk through stored cross-site scripting flaws. This issue specifically targets high-privilege users including contributors who possess the ability to upload files and modify plugin settings. The vulnerability stems from inadequate sanitization and escaping of user-controllable input within the plugin's administrative interfaces, creating an avenue for persistent malicious code execution. Attackers exploiting this weakness can inject malicious scripts that will execute whenever affected users access the plugin's settings pages, making this a particularly dangerous vulnerability for WordPress administrators who may inadvertently trigger the malicious payloads.
The technical flaw manifests in the plugin's failure to properly validate and sanitize configuration parameters that are directly rendered back to users without appropriate HTML escaping mechanisms. This allows attackers to inject malicious JavaScript code into plugin settings fields, which then gets stored in the WordPress database and executed in the context of other users' browsers when they access the affected administrative interfaces. The vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws where untrusted data is improperly incorporated into web pages without adequate validation or escaping. The stored nature of this XSS vulnerability means that the malicious code persists and affects multiple users over time rather than requiring immediate exploitation during a single session.
The operational impact of this vulnerability extends beyond simple script execution as it enables attackers to perform various malicious activities including session hijacking, credential theft, and data exfiltration. Contributors with access to the plugin settings can potentially escalate their privileges or compromise the entire WordPress installation by leveraging the stored XSS to gain unauthorized access to administrative functions. This vulnerability particularly affects WordPress environments where contributors have elevated permissions or where multiple users interact with the plugin's administrative interfaces. The threat is amplified because the attack requires minimal user interaction beyond accessing the plugin settings, making it a stealthy and effective vector for persistent compromise. Organizations using vulnerable versions of this plugin face significant risk of unauthorized access, data breaches, and potential full system compromise.
Mitigation strategies for CVE-2023-4811 primarily involve immediate patching to version 4.23.3 or later, which addresses the sanitization and escaping deficiencies in the plugin's settings handling. Administrators should also implement additional security measures including regular security audits of installed plugins, monitoring for unauthorized modifications to plugin settings, and implementing strict access controls to limit contributor privileges where possible. The principle of least privilege should be enforced by restricting plugin access to only users who absolutely require these capabilities, while also ensuring that all users maintain current WordPress core and plugin versions. Network-level monitoring can help detect suspicious activity patterns related to file uploads and settings modifications, and implementing content security policies can provide additional protection against script execution. Organizations should also conduct regular vulnerability assessments to identify and remediate similar issues in other plugins and themes, as this vulnerability demonstrates the importance of proper input validation and output escaping in web applications. The ATT&CK framework categorizes this vulnerability under T1566 for credential access through social engineering and T1059 for command and scripting interpreter, highlighting the multi-faceted attack potential that arises from such persistent XSS flaws in content management systems.