CVE-2023-27997:Heap-based buffer overflow vulnerability in FortiOS and FortiProxy SSL-VPN allows remote code execution.

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A critical heap-based buffer overflow vulnerability (CWE-122) affects multiple versions of FortiOS and FortiProxy SSL-VPN. This vulnerability allows remote attackers to execute arbitrary code or commands by sending specially crafted requests to affected systems. The vulnerability impacts FortiOS versions 7.2.4 and below, 7.0.11 and below, 6.4.12 and below, 6.0.16 and below, as well as FortiProxy versions 7.2.3 and below, 7.0.9 and below, 2.0.12 and below, and all versions of 1.2 and 1.1.

Overview

This vulnerability (CVE-2023-27997) is a heap-based buffer overflow in the SSL-VPN functionality of FortiOS and FortiProxy products. The issue occurs when processing specifically crafted requests, allowing attackers to potentially execute arbitrary code with the privileges of the affected service. Since SSL-VPN services are typically exposed to the internet, this vulnerability presents a significant risk as it can be exploited remotely without authentication. Successful exploitation could lead to complete system compromise, allowing attackers to gain unauthorized access to the network, intercept traffic, or use the compromised system as a launching point for further attacks.

Remediation

To address this vulnerability, organizations should:

  1. Update to the following fixed versions or later:
    • FortiOS: 7.2.5+, 7.0.12+, 6.4.13+, 6.2.15+ (or newer)
    • FortiProxy: 7.2.4+, 7.0.10+, 2.0.13+ (or newer)
  2. If immediate patching is not possible, consider temporarily disabling SSL-VPN functionality until updates can be applied.
  3. Implement network segmentation to limit the potential impact of exploitation.
  4. Monitor logs for suspicious SSL-VPN access attempts.
  5. Implement additional network security controls such as IP restrictions for VPN access where possible.
  6. Follow Fortinet security best practices for hardening FortiOS and FortiProxy deployments.

References

  1. Fortinet PSIRT Advisory: https://fortiguard.com/psirt/FG-IR-23-097
  2. Common Weakness Enumeration (CWE-122): https://cwe.mitre.org/data/definitions/122.html
  3. MITRE CVE Entry: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-27997
  4. Fortinet Security Advisories: https://www.fortiguard.com/psirt

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

Focus on What Matters

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

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