CVE-2020-7228 in Calculated Fields Form Plugin
Summary
by MITRE
The Calculated Fields Form plugin through 1.0.353 for WordPress suffers from multiple Stored XSS vulnerabilities present in the input forms. These can be exploited by an authenticated user.
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Analysis
by VulDB Data Team • 03/25/2024
The Calculated Fields Form plugin for WordPress represents a critical security vulnerability through version 1.0.353 that exposes users to multiple stored cross-site scripting attacks. This vulnerability specifically affects the input forms functionality within the plugin, creating a persistent threat vector that can be exploited by authenticated users who possess sufficient privileges to modify form configurations. The stored nature of these XSS vulnerabilities means that malicious payloads injected by an attacker can persist within the plugin's data storage and execute whenever legitimate users interact with the affected forms, making this particularly dangerous for environments where multiple users have access to form management capabilities.
The technical flaw stems from inadequate input validation and output sanitization within the plugin's form processing mechanisms. When authenticated users submit form data containing malicious script payloads, these inputs are not properly escaped or filtered before being stored in the WordPress database. The vulnerability manifests when the plugin renders these stored form elements back to users, executing the malicious JavaScript code in the context of the victim's browser session. This creates a persistent threat where attackers can establish backdoors, steal session cookies, perform unauthorized actions on behalf of users, or redirect victims to malicious websites without requiring additional authentication for subsequent attacks.
The operational impact of this vulnerability extends beyond simple data corruption or display issues, as it can enable attackers to escalate privileges within the WordPress environment. An authenticated user with form editing capabilities can inject malicious scripts that target other users who access the affected forms, potentially compromising entire user sessions and enabling further exploitation. The vulnerability affects the plugin's core functionality of processing and displaying user input, making it a significant threat to any WordPress site utilizing the Calculated Fields Form plugin. Attackers can leverage this weakness to perform session hijacking, deface websites, or establish persistent access points within the target environment, particularly in multi-user scenarios where administrators might be tricked into interacting with malicious form elements.
Mitigation strategies should prioritize immediate patching of the plugin to version 1.0.354 or later, which contains the necessary fixes for the stored XSS vulnerabilities. Administrators should implement strict input validation measures and sanitize all form inputs before storage, ensuring that any potentially malicious payloads are neutralized through proper encoding or filtering mechanisms. The principle of least privilege should be enforced by limiting form management capabilities to only essential administrators and implementing additional security layers such as web application firewalls that can detect and block suspicious script patterns. Security monitoring should be enhanced to detect unusual form modifications and potential injection attempts, with regular audits of form configurations to identify any unauthorized changes. Organizations should also consider implementing content security policies that restrict script execution within the plugin's interface and establish regular vulnerability scanning procedures to identify similar issues in other third-party plugins. This vulnerability aligns with CWE-79 which addresses cross-site scripting flaws, and represents a clear violation of the principle of input sanitization that should be maintained throughout all web application development processes.