CVE-2021-37391:Stored XSS vulnerability in Chamilo LMS 1.11.14 allows unprivileged users to execute arbitrary code through the social network invitation feature.

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A stored Cross-Site Scripting (XSS) vulnerability exists in Chamilo LMS version 1.11.14. The vulnerability allows unprivileged users to send malicious invitation messages to other users, including administrators, through the social network invitation feature. The vulnerability is present in the files main/social/search.php and main/inc/lib/social.lib.php. When the victim opens the invitation message, the attacker can steal cookies or execute arbitrary JavaScript code in the victim's browser context, potentially leading to account takeover or other malicious actions.

Overview

Chamilo LMS is an open-source learning management system used by educational institutions and organizations. The vulnerability (CVE-2021-37391) is a stored XSS issue that affects version 1.11.14 of the platform. The vulnerability exists in the social network invitation feature, where user input is not properly sanitized before being stored and displayed to other users. This allows attackers to inject malicious JavaScript code that executes when the victim views the invitation message. The vulnerability is particularly concerning because it can be used to target administrators, potentially leading to full system compromise. The issue has been classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting.

Remediation

To remediate this vulnerability, system administrators should:

  1. Update Chamilo LMS to a version that includes the security patch. The fix has been implemented in a commit with ID de43a77049771cce08ea7234c5c1510b5af65bc8.

  2. If immediate updating is not possible, consider implementing the following temporary mitigations:

    • Disable the social network invitation feature until the system can be updated
    • Implement additional input validation and output encoding at the web application firewall level
    • Monitor for suspicious invitation messages and user activities

  3. Educate administrators and privileged users about the risks of opening invitation messages from unknown or untrusted users until the system is patched.

  4. After applying the patch, review system logs for any signs of exploitation and verify that the vulnerability has been properly addressed.

References

  1. Detailed vulnerability analysis and exploit information: https://gitbook.seguranca-informatica.pt/cve-and-exploits/cves/chamilo-lms-1.11.14-xss-vulnerabilities

  2. Security patch commit: https://github.com/chamilo/chamilo-lms/commit/de43a77049771cce08ea7234c5c1510b5af65bc8

  3. CWE-79: Improper Neutralization of Input During Web Page Generation (Cross-site Scripting): https://cwe.mitre.org/data/definitions/79.html

  4. MITRE CVE entry: CVE-2021-37391

Industry ExposureMost to least
This section illustrates the prevalence of a specific Common Vulnerabilities and Exposures (CVE) across various industries based on customer reports. The ranking displays industries from the most to least affected by this particular vulnerability, offering valuable insight into where this CVE has been most frequently observed. This information can help organizations within these sectors prioritize their security efforts, understand their relative risk exposure compared to their peers, and focus remediation strategies where they are most needed. By understanding the industry-specific impact, organizations can make more informed decisions regarding patching, resource allocation, and overall risk management related to this CVE.

  1. Accommodation & Food Services
    Accommodation & Food Services
  2. Administrative, Support, Waste Management & Remediation Services
    Administrative, Support, Waste Management & Remediation Services
  3. Agriculture, Forestry Fishing & Hunting
    Agriculture, Forestry Fishing & Hunting
  4. Arts, Entertainment & Recreation
    Arts, Entertainment & Recreation
  5. Construction
    Construction
  6. Educational Services
    Educational Services
  7. Finance and Insurance
    Finance and Insurance
  8. Health Care & Social Assistance
    Health Care & Social Assistance
  9. Information
    Information
  10. Management of Companies & Enterprises
    Management of Companies & Enterprises
  11. Manufacturing
    Manufacturing
  12. Mining
    Mining
  13. Other Services (except Public Administration)
    Other Services (except Public Administration)
  14. Professional, Scientific, & Technical Services
    Professional, Scientific, & Technical Services
  15. Public Administration
    Public Administration
  16. Real Estate Rental & Leasing
    Real Estate Rental & Leasing
  17. Retail Trade
    Retail Trade
  18. Transportation & Warehousing
    Transportation & Warehousing
  19. Utilities
    Utilities
  20. Wholesale Trade
    Wholesale Trade

Focus on What Matters

  1. See Everything.
  2. Identify True Risk.
  3. Proactively Mitigate Threats.

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