CVE-2024-4704 in Contact Form 7 Plugin
Summary
by MITRE • 06/27/2024
The Contact Form 7 WordPress plugin before 5.9.5 has an open redirect that allows an attacker to utilize a false URL and redirect to the URL of their choosing.
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Analysis
by VulDB Data Team • 06/29/2024
The Contact Form 7 WordPress plugin version 5.9.4 and earlier contains a critical open redirect vulnerability that exposes WordPress sites to malicious redirection attacks. This vulnerability exists within the plugin's form processing logic where user-supplied input is not properly validated before being used in redirect operations. The flaw allows attackers to craft malicious URLs that, when clicked, will redirect users to arbitrary destinations controlled by the attacker rather than the intended website. This type of vulnerability falls under CWE-601 which specifically addresses open redirect vulnerabilities where applications redirect users to untrusted domains without proper validation. The issue is particularly dangerous because it can be exploited through various attack vectors including phishing campaigns, social engineering, and cross-site scripting scenarios where users are tricked into clicking malicious links.
The technical implementation of this vulnerability stems from insufficient input sanitization and validation within the plugin's redirect handling mechanism. When users submit forms through Contact Form 7, the plugin processes redirect parameters that are typically configured by site administrators. However, the plugin fails to properly validate or sanitize these parameters, allowing attackers to inject malicious URLs directly into the redirect chain. This creates a scenario where an attacker can manipulate the redirect URL to point to malicious domains, potentially leading to credential theft, malware distribution, or further exploitation of the victim's session. The vulnerability is particularly concerning because it operates at the application level within the WordPress ecosystem, making it difficult to detect through standard network monitoring tools and requiring specific application-level inspection to identify.
The operational impact of this vulnerability extends beyond simple redirection attacks and can significantly compromise user security and trust in the affected websites. When exploited, attackers can redirect users to phishing sites that closely mimic legitimate banking or social media platforms, leading to credential theft and financial fraud. The vulnerability also enables more sophisticated attack chains where initial redirection leads to exploitation of other vulnerabilities on the target site or provides a stepping stone for further reconnaissance activities. According to ATT&CK framework, this vulnerability maps to T1566 which covers social engineering techniques, and T1071 which addresses application layer protocols. The attack surface is particularly wide since Contact Form 7 is one of the most popular WordPress plugins with over 5 million active installations, making the potential impact of this vulnerability widespread across numerous websites and organizations that rely on WordPress for their online presence.
Organizations affected by this vulnerability should immediately update to Contact Form 7 version 5.9.5 or later, which includes patches specifically addressing the open redirect flaw. Additionally, administrators should conduct thorough security audits of their WordPress installations to identify any other potentially vulnerable plugins or themes that may exhibit similar behaviors. Network administrators should implement URL filtering and monitoring solutions that can detect suspicious redirect patterns and alert security teams to potential exploitation attempts. Security teams should also review their incident response procedures to ensure proper handling of redirect-based attacks and consider implementing web application firewalls that can block malicious redirect attempts. The vulnerability highlights the importance of proper input validation and output encoding practices as recommended by OWASP Top Ten and other security standards, emphasizing that all user-supplied data should be treated as potentially malicious until properly validated and sanitized. Organizations should also consider implementing Content Security Policy headers and other web security measures that can help prevent or mitigate the impact of open redirect vulnerabilities in their web applications.