CVE-2011-3863 in RedLine
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the RedLine theme before 1.66 for WordPress allows remote attackers to inject arbitrary web script or HTML via the s parameter.
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Analysis
by VulDB Data Team • 02/03/2025
The CVE-2011-3863 vulnerability represents a critical cross-site scripting flaw discovered in the RedLine WordPress theme prior to version 1.66. This vulnerability resides within the theme's handling of user input parameters, specifically the 's' parameter which is commonly used for search functionality within WordPress installations. The flaw enables remote attackers to execute malicious scripts in the context of victim browsers, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of users. The vulnerability affects a significant number of WordPress sites that relied on the RedLine theme, creating a widespread attack surface for malicious actors targeting content management systems.
The technical implementation of this XSS vulnerability stems from inadequate input sanitization and output encoding within the RedLine theme's search functionality. When the 's' parameter is processed without proper validation or sanitization, malicious payloads can be injected directly into the theme's template files. This occurs because the theme fails to properly escape or filter user-supplied input before rendering it in web pages, allowing attackers to inject script tags or other malicious HTML content. The vulnerability is classified as a reflected XSS attack since the malicious code is reflected back to users through the vulnerable parameter without being stored on the server. This flaw aligns with CWE-79 which specifically addresses cross-site scripting vulnerabilities in web applications, where improper validation of input data leads to execution of malicious scripts in user browsers.
The operational impact of CVE-2011-3863 extends beyond simple script injection, as it provides attackers with a foothold for more sophisticated attacks within compromised WordPress environments. Victims browsing affected sites could unknowingly execute malicious code that steals cookies, session tokens, or other sensitive information, potentially leading to complete account compromise. Attackers could leverage this vulnerability to redirect users to phishing sites, inject malware delivery mechanisms, or perform unauthorized administrative actions if users have elevated privileges. The vulnerability also enables social engineering attacks where malicious scripts can modify page content to deceive users or harvest their input data. From an attacker's perspective, this vulnerability fits within the ATT&CK framework under T1566 (Phishing) and T1059 (Command and Scripting Interpreter) categories, as it allows for both initial compromise and subsequent execution of malicious payloads.
Organizations affected by this vulnerability should immediately implement multiple layers of mitigation strategies to protect their WordPress installations. The primary remediation involves upgrading the RedLine theme to version 1.66 or later, which contains proper input validation and output encoding fixes. Additionally, implementing Content Security Policy headers can provide an additional defense-in-depth measure by restricting script execution sources and preventing unauthorized code injection. Web application firewalls should be configured to detect and block suspicious parameter values containing script tags or common XSS attack patterns. Regular security auditing of WordPress themes and plugins remains crucial, as this vulnerability demonstrates how seemingly benign functionality can introduce critical security risks. The incident underscores the importance of following secure coding practices, including input validation, output encoding, and regular security updates as recommended by industry standards such as OWASP Top Ten and NIST cybersecurity guidelines.