CVE-2017-18491 in contact-form-plugin Plugin
Summary
by MITRE
The contact-form-plugin plugin before 4.0.6 for WordPress has multiple XSS issues.
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Analysis
by VulDB Data Team • 11/23/2023
The contact-form-plugin for WordPress versions prior to 4.0.6 contains multiple cross-site scripting vulnerabilities that pose significant security risks to web applications. These vulnerabilities arise from insufficient input validation and output sanitization within the plugin's contact form handling mechanisms, creating attack vectors that can be exploited by malicious actors to execute arbitrary JavaScript code in the context of affected websites. The flaw affects the core functionality of WordPress contact forms, which are commonly used for user interactions, feedback collection, and communication between website visitors and administrators. The vulnerability stems from the plugin's failure to properly sanitize user-supplied data before rendering it in web pages, allowing attackers to inject malicious scripts that persist in the application's data storage or execution environment.
The technical implementation of these XSS vulnerabilities demonstrates a classic failure in secure coding practices where user input flows directly into HTML output without appropriate sanitization or encoding mechanisms. The plugin's form processing logic does not adequately validate or escape special characters in form field data, particularly in fields such as name, email, subject, and message inputs. This allows attackers to inject script tags, event handlers, or other malicious payloads that execute when legitimate users view the affected pages or when administrators review submitted form data. The vulnerability affects both reflected and stored XSS scenarios, depending on how the data is processed and stored within the plugin's architecture. Attackers can leverage these flaws to steal session cookies, redirect users to malicious sites, deface websites, or perform actions on behalf of authenticated users.
The operational impact of this vulnerability extends beyond simple data corruption or display issues, as it creates persistent security risks that can compromise entire WordPress installations. When exploited, these XSS vulnerabilities can enable attackers to establish persistent access to websites by stealing administrator credentials or session tokens, leading to full compromise of the affected WordPress environment. The vulnerability affects not only the end users who interact with contact forms but also administrators who may unknowingly execute malicious code while reviewing submitted form data. The stored XSS nature of some variants means that malicious scripts can remain active for extended periods, continuously affecting visitors until the vulnerability is patched or the malicious content is manually removed. This creates a significant risk for websites that rely heavily on user-generated content through contact forms, as the attack surface expands with each form submission.
Mitigation strategies for CVE-2017-18491 should prioritize immediate plugin updates to version 4.0.6 or later, which contain the necessary sanitization and validation fixes. Organizations should implement comprehensive input validation at multiple layers of their application architecture, including both client-side and server-side validation mechanisms. The principle of least privilege should be enforced when processing form data, ensuring that user inputs are properly escaped before being rendered in any HTML context. Security measures should include regular security audits of third-party plugins, implementation of web application firewalls, and monitoring of unusual form submission patterns that may indicate exploitation attempts. This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and corresponds to techniques described in the ATT&CK framework under web application attacks and credential access phases. Organizations should also consider implementing Content Security Policy headers to provide additional defense-in-depth measures against script execution vulnerabilities, while maintaining regular patch management processes to address similar issues in other WordPress components and plugins.