CVE-2018-14846 in Mondula Multi Step Form Plugin
Summary
by MITRE
The Mondula Multi Step Form plugin before 1.2.8 for WordPress has multiple stored XSS via wp-admin/admin-ajax.php.
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Analysis
by VulDB Data Team • 04/22/2020
The Mondula Multi Step Form plugin for WordPress contains a critical stored cross-site scripting vulnerability that affects versions prior to 1.2.8. This vulnerability exists within the wp-admin/admin-ajax.php endpoint which serves as a central AJAX handler for WordPress administrative functions. The flaw allows authenticated attackers with sufficient privileges to inject malicious scripts into form data that gets stored in the database and subsequently executed when other users view the affected forms. The vulnerability represents a classic stored XSS attack vector where malicious input persists in the application's database and executes against unsuspecting users who interact with the compromised content.
The technical implementation of this vulnerability stems from inadequate input sanitization and output escaping within the plugin's form processing logic. When administrators or users submit form data through the multi-step form interface, the plugin fails to properly validate and sanitize the input before storing it in the WordPress database. The wp-admin/admin-ajax.php endpoint processes these requests without sufficient security controls to prevent malicious script injection. This flaw typically occurs when the plugin relies on user-supplied data without implementing proper HTML entity encoding or content security policies that would prevent script execution in the browser context.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with persistent access to the compromised WordPress environment. An attacker with access to the administrative interface or the ability to submit malicious form data can establish a foothold that persists across user sessions and system restarts. The stored nature of the XSS means that any user who views the compromised form data becomes a potential victim of the attack, making this vulnerability particularly dangerous in multi-user environments where administrators and regular users all interact with the same form data. The vulnerability can be exploited to steal session cookies, redirect users to malicious sites, or perform unauthorized administrative actions on behalf of legitimate users.
Security mitigation strategies for this vulnerability involve immediate patching of the Mondula Multi Step Form plugin to version 1.2.8 or later, which includes proper input validation and output sanitization measures. Organizations should implement comprehensive input validation at multiple layers including client-side and server-side checks, ensuring that all user-supplied data undergoes proper sanitization before being stored in the database. The implementation of Content Security Policy headers can provide an additional layer of protection by restricting script execution within the browser context. Network monitoring should be enhanced to detect anomalous AJAX requests that might indicate exploitation attempts. According to CWE standards, this vulnerability maps to CWE-79 which specifically addresses cross-site scripting flaws, while the ATT&CK framework categorizes this under T1059.005 for command and scripting interpreter and T1566 for credential access through social engineering techniques that could be facilitated by the XSS payload. Organizations should also conduct thorough security assessments of all installed WordPress plugins to identify similar vulnerabilities and implement automated patch management processes to ensure timely remediation of security issues.