CVE-2008-6404 in Thyme
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in add_calendars.php in eXtrovert Software Thyme 1.3 allows remote attackers to inject arbitrary web script or HTML via the callback parameter.
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Analysis
by VulDB Data Team • 06/22/2025
The CVE-2008-6404 vulnerability represents a classic cross-site scripting flaw in the eXtrovert Software Thyme 1.3 calendar application that specifically targets the add_calendars.php script. This vulnerability exists within the callback parameter handling mechanism, creating a pathway for remote attackers to execute malicious web scripts or HTML content within the context of other users' browsers. The flaw demonstrates a critical weakness in input validation and output encoding practices, where user-supplied data flows directly into the application's response without adequate sanitization or contextual escaping. Such vulnerabilities fall under the CWE-79 category of Cross-Site Scripting, which is one of the most prevalent and dangerous web application security flaws identified by the CWE database. The vulnerability operates by leveraging the application's failure to properly validate or escape user-provided input before rendering it in web pages, allowing attackers to inject malicious payloads that execute in the victim's browser context.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it enables attackers to perform session hijacking, redirect users to malicious sites, or execute arbitrary commands within the victim's browser environment. When an attacker crafts a malicious callback parameter and persuades a user to click on the resulting link or visit a compromised page, the injected script executes with the privileges and permissions of the victim user. This creates a significant risk for authenticated users who may have elevated privileges within the Thyme application, potentially allowing attackers to escalate their access or manipulate calendar data. The vulnerability affects the core functionality of the calendar application, making it particularly dangerous as it could compromise the integrity of calendar entries, user data, and potentially the entire application's security posture. According to ATT&CK framework, this vulnerability maps to T1531 - Account Access Token Manipulation and T1059 - Command and Scripting Interpreter, as it enables attackers to execute malicious scripts and potentially escalate privileges through compromised user sessions.
Mitigation strategies for CVE-2008-6404 require immediate implementation of proper input validation and output encoding measures throughout the application's codebase. The primary fix involves implementing strict validation of the callback parameter to ensure it conforms to expected formats and does not contain malicious script content. Additionally, all user-supplied data must be properly escaped or encoded before being rendered in web responses, particularly when dealing with dynamic content generation. The application should employ context-appropriate encoding mechanisms such as HTML entity encoding, JavaScript escaping, or URL encoding based on where the data appears in the output. Security headers including Content Security Policy (CSP) should be implemented to provide additional defense-in-depth against XSS attacks. Organizations should also conduct comprehensive code reviews and implement automated security testing to identify similar vulnerabilities in other application components. Regular security updates and patches should be applied promptly, and the application should be configured to disable unnecessary features or parameters that could serve as attack vectors. The vulnerability highlights the importance of following secure coding practices and demonstrates how seemingly minor input handling flaws can create significant security risks that compromise the entire application ecosystem.