CVE-2011-3850 in Atahualpa
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Atahualpa theme before 3.6.8 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 • 02/02/2025
The CVE-2011-3850 vulnerability represents a critical cross-site scripting flaw within the Atahualpa WordPress theme, specifically affecting versions prior to 3.6.8. This vulnerability exposes WordPress installations to malicious injection attacks that can compromise user sessions and data integrity. The flaw manifests through the improper handling of the s parameter in the theme's code, creating an avenue for remote attackers to execute arbitrary web scripts or HTML content within the context of affected websites. The vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is classified as a fundamental web application security weakness that allows attackers to inject client-side scripts into web pages viewed by other users. This particular implementation vulnerability demonstrates a classic failure in input validation and output encoding within the theme's template processing system.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious input containing script tags or HTML content and passes it through the s parameter of the WordPress theme's URL structure. When the vulnerable theme processes this parameter without proper sanitization, the injected content gets rendered directly into the web page, allowing the malicious script to execute in the browser context of unsuspecting visitors. This creates a persistent threat vector where attackers can steal cookies, session tokens, or perform other malicious activities such as defacement, data exfiltration, or redirecting users to phishing sites. The vulnerability operates at the application layer and requires no special privileges to exploit, making it particularly dangerous for widespread deployment across multiple WordPress installations. The issue aligns with ATT&CK technique T1566.001 for initial access through malicious content and T1059.001 for command and control through script injection.
The operational impact of CVE-2011-3850 extends beyond simple script execution, as it can enable attackers to establish persistent backdoors, harvest user credentials, or manipulate website content to spread malware. Website administrators running vulnerable versions of the Atahualpa theme face significant risk of user data compromise and potential reputation damage. The vulnerability affects not just the theme's functionality but also the overall security posture of WordPress installations, as it allows attackers to bypass traditional security measures that might protect other parts of the application. Organizations relying on WordPress for content management must consider the cascading effects of such vulnerabilities, particularly in environments where multiple users interact with the platform or where sensitive data is processed. The vulnerability demonstrates the critical importance of theme security in WordPress ecosystems, as third-party themes often contain code that can introduce security weaknesses not present in the core WordPress application itself.
Mitigation strategies for CVE-2011-3850 primarily focus on immediate remediation through theme updates to version 3.6.8 or later, which incorporates proper input sanitization and output encoding mechanisms. Administrators should implement comprehensive security monitoring to detect potential exploitation attempts and establish regular patch management procedures to prevent similar vulnerabilities from arising in the future. Input validation should be strengthened at multiple levels including the application layer and database input sanitization to prevent malicious content from being processed. The implementation of Content Security Policy headers can provide additional protection against script injection attacks, while regular security audits of WordPress themes and plugins can help identify similar vulnerabilities before they are exploited. Organizations should also consider implementing web application firewalls to detect and block suspicious parameter values, and maintain up-to-date backups to facilitate rapid recovery in case of successful exploitation attempts. The vulnerability underscores the necessity of following security best practices such as the principle of least privilege and regular security assessments to maintain robust defenses against evolving threat landscapes.