CVE-2004-1506 in Webcalendar
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in WebCalendar allow remote attackers to inject arbitrary web script via (1) view_entry.php, (2) view_d.php, (3) usersel.php, (4) datesel.php, (5) trailer.php, or (6) styles.php, as demonstrated using img srg tags.
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Analysis
by VulDB Data Team • 06/22/2018
The vulnerability described in CVE-2004-1506 represents a critical cross-site scripting flaw affecting the WebCalendar application, a widely used web-based calendar management system. This vulnerability falls under the Common Weakness Enumeration category CWE-79, which specifically addresses improper neutralization of input during web page generation, commonly known as cross-site scripting. The flaw exists in multiple PHP script files including view_entry.php, view_d.php, usersel.php, datesel.php, trailer.php, and styles.php, indicating a systemic issue in the application's input validation and output encoding mechanisms. Attackers can exploit these vulnerabilities by injecting malicious JavaScript code through img src tags, which demonstrates the breadth of attack vectors available to threat actors.
The technical exploitation of this vulnerability occurs when the WebCalendar application fails to properly sanitize user input before rendering it in web pages. When users interact with the calendar system and provide input through the affected scripts, the application processes this data without adequate validation or encoding, allowing malicious payloads to be executed in the context of other users' browsers. The img src tag demonstration shows that attackers can leverage standard HTML elements to inject script code, making the attack surface particularly broad and easily exploitable. This type of vulnerability enables attackers to perform various malicious activities including session hijacking, credential theft, and redirection to malicious websites.
The operational impact of CVE-2004-1506 extends beyond simple data theft, as it provides attackers with persistent access to the calendar system and potentially to other applications within the same domain. The vulnerability can be exploited by remote attackers without requiring authentication, making it particularly dangerous for organizations using WebCalendar in production environments. Once compromised, attackers can manipulate calendar entries, view sensitive information, and potentially escalate their access to other system components. The multi-script nature of the vulnerability means that even if one entry point is patched, other vectors remain exploitable, creating a comprehensive attack surface that can be leveraged for extended periods of time.
Organizations should implement comprehensive input validation and output encoding measures to address this vulnerability, following security best practices outlined in the OWASP Top Ten and NIST guidelines for web application security. The recommended mitigations include implementing proper HTML escaping for all user-supplied input, deploying web application firewalls, and conducting regular security audits of web applications. Additionally, the principle of least privilege should be enforced, ensuring that calendar applications have minimal required permissions and that user input is strictly validated before processing. The vulnerability also highlights the importance of regular security updates and vulnerability assessments, as demonstrated by the fact that this issue was present in versions of WebCalendar released in 2004, indicating a lack of proper input sanitization in the application's core functionality.