CVE-2015-2220 in Ninja Forms
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the Ninja Forms plugin before 2.8.9 for WordPress allow (1) remote attackers to inject arbitrary web script or HTML via the ninja_forms_field_1 parameter in a ninja_forms_ajax_submit action to wp-admin/admin-ajax.php or (2) remote administrators to inject arbitrary web script or HTML via the fields[1] parameter to wp-admin/post.php.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 05/01/2022
The vulnerability described in CVE-2015-2220 represents a critical cross-site scripting flaw affecting the Ninja Forms WordPress plugin version 2.8.8 and earlier. This vulnerability stems from inadequate input validation and output sanitization within the plugin's handling of user-supplied data in administrative contexts. The flaw manifests in two distinct attack vectors that exploit different entry points within the WordPress administration interface, creating multiple pathways for malicious actors to execute harmful scripts against unsuspecting users.
The technical implementation of this vulnerability involves the plugin's failure to properly sanitize user input parameters before processing them in server-side operations. Attackers can manipulate the ninja_forms_field_1 parameter through the ninja_forms_ajax_submit action endpoint located at wp-admin/admin-ajax.php, which serves as a central AJAX handler for WordPress administrative functions. Additionally, the vulnerability extends to the wp-admin/post.php endpoint where administrators can be targeted through manipulation of the fields[1] parameter. Both attack vectors demonstrate the plugin's insufficient validation of input data, allowing malicious scripts to be injected and executed within the context of authenticated user sessions.
The operational impact of this vulnerability is significant as it enables remote code execution through the exploitation of XSS flaws in the WordPress administrative interface. An attacker with access to the plugin's AJAX submission endpoint can inject malicious scripts that will execute in the browser of any user who views the affected pages, potentially leading to session hijacking, data theft, or further compromise of the WordPress installation. The vulnerability particularly dangerous because it targets the administrative interface, meaning that successful exploitation could allow attackers to gain elevated privileges and potentially take complete control of the WordPress site.
This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and demonstrates the importance of implementing proper input validation and output encoding throughout the application lifecycle. From an ATT&CK perspective, this vulnerability maps to T1059.007 for command and scripting interpreter, specifically through the execution of malicious JavaScript in user browsers. The exploitation of this vulnerability also relates to T1566 for credential access through the potential for session hijacking and privilege escalation. Organizations should prioritize immediate patching to version 2.8.9 or later, as this update addresses the insufficient input validation that allowed these XSS payloads to be executed within the WordPress administrative context.
The remediation strategy should include not only updating to the patched version but also implementing additional security measures such as input validation at multiple layers, output encoding for all dynamic content, and regular security auditing of WordPress plugins. Organizations should also consider implementing web application firewalls and monitoring for suspicious AJAX requests to detect potential exploitation attempts. The vulnerability underscores the critical importance of maintaining up-to-date WordPress plugins and following secure coding practices that prevent injection flaws in administrative interfaces where privileged access exists.