Key Information Vulnerability Overview Vulnerability Type: Reflected Cross-Site Scripting (XSS) Affected Versions: LuxCal 4.5.2 and earlier CVE ID: CVE-2020-26799 CVSS Score: 6.1 (Medium) Technical Details Affected Component: RSS feed link parameter in the file Attack Vector: Network (Unauthenticated) Vulnerability Description In the file, malicious JavaScript code can be injected via the RSS feed link parameter into the HTTP response. Due to insufficient input sanitization, arbitrary JavaScript code can be executed in the victim’s browser. Impact Information Disclosure: Access to sensitive user data and session information Cookie Theft: Stealing authentication cookies to perform session hijacking Social Engineering Attacks: Displaying fake login forms for phishing Cross-Site Request Forgery (CSRF): Performing actions on behalf of the victim Credential Collection: Capturing user credentials via fake forms Malware Distribution: Redirecting users to malicious websites Attack Scenarios Scenario 1: Session Hijacking – Attackers can craft a malicious URL to steal user session cookies and send them to an attacker-controlled server. Scenario 2: Credential Theft – Attackers can inject JavaScript to display a fake login form, capturing credentials when users attempt to log in. Scenario 3: Webpage Tampering – Malicious scripts can alter page content, display unauthorized information, or redirect users to malicious sites. Proof of Concept A video link demonstrating the exploitation of this vulnerability is provided. Attack Vector Network-Based: Remote exploitation via crafted URLs No Authentication Required: Exploitation does not require authentication Social Engineering: Users may be tricked into clicking malicious links Email/Messaging Platforms: Malicious URLs can be distributed via email or messaging services Affected Organizations As of October 2020, the vulnerable version of LuxCal was still in use by multiple organizations, including enterprise environments, highlighting the importance of keeping software up to date. Mitigation Measures Immediate Actions: - Upgrade to LuxCal v4.7.x or later - Implement proper input validation - Ensure all dynamic content is properly encoded before output - Implement Content Security Policy (CSP) headers to prevent XSS execution Recommended Fixes: - Example code demonstrates how to escape inputs and use comprehensive escaping libraries. Security Headers Example configuration for recommended security headers. Timeline Discovery: October 2020 (during penetration testing) CVE Assignment: CVE-2020-26799 assigned Vendor Status: LuxCal v4.7.x released (released in 2018) Public Disclosure: July 20, 2020 Vendor Information Vendor: LuxSoft Product: LuxCal Calendar Software Vendor Website: Download page link provided References Includes links to related CVEs, LuxCal download page, proof-of-concept video, and OWASP XSS Prevention Cheat Sheet. Acknowledgments This vulnerability was discovered during a scheduled penetration test and responsibly disclosed.