CVE-2023-21709:Microsoft Exchange Server Elevation of Privilege Vulnerability (CVE-2023-21709) allows attackers to potentially gain unauthorized access through a brute force attack.

splash
Back

Description Preview

CVE-2023-21709 is an elevation of privilege vulnerability in Microsoft Exchange Server that could allow an attacker to gain unauthorized privileges. The vulnerability is classified as CWE-307 (Improper Restriction of Excessive Authentication Attempts), suggesting that the issue relates to insufficient protection against brute force attacks. This security flaw could enable attackers to repeatedly attempt authentication until successful, potentially compromising Exchange Server environments.

Overview

This vulnerability affects Microsoft Exchange Server and stems from improper handling of authentication attempts. The CWE-307 classification indicates that the vulnerability allows excessive authentication attempts without proper rate limiting or lockout mechanisms. Attackers could exploit this vulnerability to perform brute force attacks against Exchange Server credentials, potentially gaining elevated privileges within the environment. Once successful, an attacker could perform unauthorized actions with the privileges of the compromised account, which could include accessing sensitive information or further compromising the system.

Remediation

Organizations should immediately apply the security updates provided by Microsoft to address this vulnerability. The patches are available through the Microsoft Update Guide referenced in the advisory. In addition to patching, organizations should:

  1. Implement multi-factor authentication for Exchange Server access
  2. Configure account lockout policies to limit failed authentication attempts
  3. Monitor authentication logs for suspicious activities or brute force attempts
  4. Implement network segmentation to limit access to Exchange Server environments
  5. Consider implementing additional authentication protection mechanisms such as CAPTCHA or time delays after failed attempts
  6. Review and audit user accounts with elevated privileges to ensure proper access control

References

  1. Microsoft Security Response Center (MSRC) Update Guide: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21709
  2. Common Weakness Enumeration (CWE-307): Improper Restriction of Excessive Authentication Attempts
  3. Microsoft Exchange Server Security Updates

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

Focus on What Matters

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

Let's talk!

background