CVE-2023-33009:Buffer overflow vulnerability in Zyxel firewall notification function allows for DoS and remote code execution.

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Description Preview

A critical buffer overflow vulnerability (CWE-120) has been identified in the notification function of multiple Zyxel firewall product lines. This vulnerability affects ATP series, USG FLEX series, USG FLEX 50(W), USG20(W)-VPN, VPN series, and ZyWALL/USG series with specific firmware versions. The flaw could allow an unauthenticated attacker to cause denial-of-service conditions or execute arbitrary code remotely on affected devices, potentially leading to complete system compromise.

Overview

The vulnerability (CVE-2023-33009) exists in the notification function of multiple Zyxel firewall products. Affected devices include:

  • ATP series firmware versions 4.60 through 5.36 Patch 1
  • USG FLEX series firmware versions 4.60 through 5.36 Patch 1
  • USG FLEX 50(W) firmware versions 4.60 through 5.36 Patch 1
  • USG20(W)-VPN firmware versions 4.60 through 5.36 Patch 1
  • VPN series firmware versions 4.60 through 5.36 Patch 1
  • ZyWALL/USG series firmware versions 4.60 through 4.73 Patch 1

This buffer overflow vulnerability is particularly concerning as it does not require authentication to exploit, making it accessible to remote attackers. Successful exploitation could result in denial-of-service conditions or remote code execution, potentially giving attackers complete control over the affected device.

Remediation

To address this vulnerability, organizations should:

  1. Update affected Zyxel firewall devices to the latest firmware versions as provided by Zyxel.
  2. For ATP series, USG FLEX series, USG FLEX 50(W), USG20(W)-VPN, and VPN series: Update to firmware version 5.36 Patch 2 or later.
  3. For ZyWALL/USG series: Update to firmware version 4.73 Patch 2 or later.
  4. If immediate patching is not possible, consider implementing network segmentation to limit access to the management interfaces of affected devices.
  5. Monitor for unusual activity on affected devices that might indicate exploitation attempts.
  6. Follow Zyxel's security best practices for firewall configuration and management.

References

  • Zyxel Security Advisory: https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-buffer-overflow-vulnerabilities-of-firewalls
  • CVE-2023-33009
  • CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Early Warning

Armis Early Warning customers received an advanced alert on this vulnerability.

Armis Alert Date
May 25, 2023
CISA KEV Date
Jun 5, 2023
11days early
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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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