CVE-2006-6669 in WebCalendar
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in export_handler.php in WebCalendar 1.0.4 and earlier allows remote attackers to inject arbitrary web script or HTML via the format parameter.
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Analysis
by VulDB Data Team • 07/18/2019
The vulnerability described in CVE-2006-6669 represents a classic cross-site scripting flaw within the WebCalendar 1.0.4 software ecosystem, specifically targeting the export_handler.php component. This issue falls under the broader category of CWE-79 Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security architectures. The vulnerability manifests when the application fails to properly sanitize user-supplied input parameters, creating an exploitable entry point for malicious actors to inject arbitrary web scripts or HTML content into web pages viewed by other users.
The technical implementation of this vulnerability occurs through the format parameter within the export_handler.php script, which processes calendar data exports. When users provide unvalidated input through this parameter, the web application directly incorporates this data into generated web pages without adequate sanitization or encoding mechanisms. This allows attackers to craft malicious payloads that execute within the context of other users' browsers, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of victims. The vulnerability exists due to insufficient input validation and output encoding practices, which are core requirements of the OWASP Top Ten security framework and align with the ATT&CK technique T1059.007 for Command and Scripting Interpreter.
The operational impact of this vulnerability extends beyond simple script injection, as it creates a persistent threat vector that can be exploited across multiple user sessions. Attackers can leverage this weakness to manipulate calendar data, inject malicious links that redirect users to phishing sites, or establish persistent backdoors through crafted export formats. The vulnerability affects all versions of WebCalendar up to and including 1.0.4, making it particularly concerning for organizations that may have legacy installations. The attack surface is significant since calendar applications are often used in enterprise environments where users trust the application interface, making social engineering aspects of exploitation more effective. This type of vulnerability also contributes to broader security posture degradation and can serve as a stepping stone for more sophisticated attacks within compromised networks.
Mitigation strategies for this vulnerability require immediate patching of the affected WebCalendar versions, as the original developers have released updates addressing the input validation shortcomings. Organizations should implement comprehensive input sanitization measures, including the use of proper output encoding for all dynamic content and the implementation of Content Security Policy headers to limit script execution. The remediation process should include thorough code review of input handling mechanisms and the adoption of secure coding practices that prevent similar issues in future development cycles. Additionally, network monitoring should be enhanced to detect suspicious export requests, and user education programs should emphasize the importance of verifying calendar data sources before interacting with exported content. These measures align with NIST SP 800-53 security controls and the broader principles of defense in depth as outlined in the MITRE ATT&CK framework.