CVE-2021-27385:Infinite Loop Vulnerability in Siemens SIMATIC HMI Panels and SINAMICS Devices

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Description Preview

A vulnerability (CWE-835: Infinite Loop) has been identified in various Siemens SIMATIC HMI Comfort Panels, Mobile Panels, WinCC Runtime Advanced, and SINAMICS drive systems. This vulnerability allows a remote attacker to send specially crafted packets to the SmartVNC device layout handler on the client side, potentially causing an infinite loop condition that results in a denial-of-service attack. The vulnerability affects multiple versions of these products prior to specific security updates.

Overview

This vulnerability (CVE-2021-27385) affects the SmartVNC device layout handler in various Siemens industrial control systems. When exploited, it can cause the system to enter an infinite loop, consuming excessive resources and potentially making the system unresponsive. This denial-of-service condition could impact industrial operations that rely on these human-machine interfaces and drive systems. The vulnerability is particularly concerning in industrial environments where system availability is critical for operational safety and productivity.

Remediation

Users should update to the following versions or later:

  • SIMATIC HMI Comfort Outdoor Panels V15: Update to V15.1 Update 6 or later
  • SIMATIC HMI Comfort Outdoor Panels V16: Update to V16 Update 4 or later
  • SIMATIC HMI Comfort Panels V15: Update to V15.1 Update 6 or later
  • SIMATIC HMI Comfort Panels V16: Update to V16 Update 4 or later
  • SIMATIC HMI KTP Mobile Panels V15: Update to V15.1 Update 6 or later
  • SIMATIC HMI KTP Mobile Panels V16: Update to V16 Update 4 or later
  • SIMATIC WinCC Runtime Advanced V15: Update to V15.1 Update 6 or later
  • SIMATIC WinCC Runtime Advanced V16: Update to V16 Update 4 or later

For SINAMICS drive systems (GH150, GL150, GM150, SH150, SL150, SM120, SM150, SM150i), consult the Siemens security advisories for specific remediation instructions, as update information is not explicitly provided in the CVE description.

If immediate patching is not possible, consider implementing network segmentation and restricting remote access to affected systems to minimize exposure.

References

  1. Siemens Security Advisory SSA-286838: https://cert-portal.siemens.com/productcert/pdf/ssa-286838.pdf
  2. Siemens Security Advisory SSA-538778: https://cert-portal.siemens.com/productcert/pdf/ssa-538778.pdf
  3. CISA ICS Advisory ICSA-21-131-12: https://us-cert.cisa.gov/ics/advisories/icsa-21-131-12
  4. Common Weakness Enumeration CWE-835 (Infinite Loop): https://cwe.mitre.org/data/definitions/835.html

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