CVE-2011-3856 in Elegant Grunge
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Elegant Grunge theme before 1.0.4 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-2011-3856 vulnerability represents a classic cross-site scripting flaw that affected the Elegant Grunge theme for WordPress installations prior to version 1.0.4. 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 environments. The flaw allows remote attackers to inject malicious web scripts or HTML code into the vulnerable application, creating a persistent security risk for users interacting with affected WordPress sites.
This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is one of the most prevalent and dangerous web application security flaws. The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the Elegant Grunge theme's search functionality. When users perform searches or when the theme processes search queries, the 's' parameter is not properly escaped or validated before being rendered back to the user's browser. This creates an opportunity for attackers to inject malicious scripts that execute in the context of other users' sessions, potentially leading to session hijacking, credential theft, or further exploitation of the compromised user accounts.
The operational impact of CVE-2011-3856 extends beyond simple script injection, as it can enable attackers to perform various malicious activities through the compromised WordPress site. An attacker could inject scripts that redirect users to phishing sites, steal cookies and session tokens, or even inject additional malicious code that could compromise the entire WordPress installation. The vulnerability is particularly dangerous because it affects a widely used theme, meaning that numerous WordPress sites could be vulnerable simultaneously. This creates a scalable attack vector that allows threat actors to compromise multiple sites with a single payload, making it an attractive target for automated exploitation campaigns.
The exploitation of this vulnerability aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to initial access and privilege escalation through web application attacks. Attackers could leverage this XSS flaw as part of a broader attack chain, potentially using it to establish a foothold in WordPress environments before progressing to more sophisticated attacks. The remediation strategy for this vulnerability involves upgrading to version 1.0.4 or later of the Elegant Grunge theme, which includes proper input sanitization and output encoding for the search parameter. Organizations should also implement additional security measures such as content security policies, input validation at multiple layers, and regular security audits of WordPress themes and plugins to prevent similar vulnerabilities from being introduced into their environments.