CVE-2011-4920 in e107
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in e107 0.7.26, and other versions before 1.0.0, allow remote attackers to inject arbitrary web script or HTML via the URL to (1) e107_images/thumb.php or (2) rate.php, (3) resend_name parameter to e107_admin/users.php, and (4) link BBCode in user signatures.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 07/11/2019
The CVE-2011-4920 vulnerability represents a critical cross-site scripting flaw affecting the e107 content management system version 0.7.26 and earlier releases prior to the 1.0.0 milestone. This vulnerability exposes multiple attack vectors within the system's web interface, creating opportunities for remote attackers to execute malicious scripts in the context of victims' browsers. The flaw stems from insufficient input validation and output sanitization mechanisms within several key components of the CMS, particularly those handling user-provided data in URL parameters and content fields.
The technical implementation of this vulnerability manifests through four distinct attack vectors that collectively demonstrate poor security practices in input handling. The first vector targets the e107_images/thumb.php script where URL parameters are not properly sanitized, allowing attackers to inject malicious JavaScript code that executes when the thumbnail image is rendered. The second vector operates through the rate.php script, where similar input validation failures permit script injection attacks. The third vector focuses on the resend_name parameter within e107_admin/users.php, exploiting administrative interfaces where user input is directly incorporated into server responses without adequate sanitization. The fourth vector targets user signature fields through BBCode processing, where the link BBCode element fails to properly escape user input, creating a persistent XSS opportunity. These vulnerabilities align with CWE-79, which specifically addresses cross-site scripting flaws in web applications.
The operational impact of CVE-2011-4920 extends beyond simple script injection, potentially enabling attackers to hijack user sessions, steal sensitive information, manipulate content, or redirect users to malicious sites. The presence of administrative interface vulnerabilities (the resend_name parameter) particularly amplifies the risk, as successful exploitation could grant attackers elevated privileges within the system. The widespread nature of the e107 CMS means that exploitation of these vulnerabilities could affect numerous websites, potentially compromising user data and system integrity. Attackers could leverage these flaws to create persistent backdoors, harvest login credentials, or manipulate website content to spread malware. The vulnerability's persistence across multiple versions indicates fundamental architectural issues in input validation that required comprehensive code review and security remediation.
Mitigation strategies for CVE-2011-4920 should prioritize immediate system updates to version 1.0.0 or later, which contain the necessary security patches. Organizations should implement comprehensive input validation and output encoding mechanisms across all user-facing interfaces, particularly those handling URL parameters and user-generated content. The principle of least privilege should be enforced by sanitizing all input data using established encoding libraries and implementing Content Security Policy headers to limit script execution. Security professionals should conduct regular vulnerability assessments focusing on input validation controls and maintain updated threat intelligence to identify similar vulnerabilities in other CMS platforms. The ATT&CK framework categorizes these vulnerabilities under T1059 for command and scripting interpreters and T1566 for credential access through social engineering, highlighting the broader threat landscape that these XSS vulnerabilities create. Additionally, implementing web application firewalls and regular security monitoring can help detect and prevent exploitation attempts while maintaining operational continuity during remediation efforts.