CVE-2020-3111:Cisco IP Phone Cisco Discovery Protocol Remote Code Execution Vulnerability

splash
Back

Description Preview

A critical vulnerability in the Cisco Discovery Protocol (CDP) implementation for Cisco IP Phones allows unauthenticated, adjacent attackers to remotely execute code with root privileges or cause a denial of service condition. The vulnerability (CVE-2020-3111) stems from missing validation checks when processing CDP messages, enabling attackers to send crafted packets that can compromise affected devices.

Overview

This vulnerability affects the Cisco Discovery Protocol implementation in Cisco IP Phones. Due to insufficient input validation (CWE-20: Improper Input Validation), an adjacent attacker can send specially crafted CDP packets to an affected device. Since CDP is a Layer 2 protocol, the attacker must be in the same broadcast domain as the target device.

The vulnerability can be exploited in two ways:

  1. Remote code execution with root privileges, giving attackers complete control over the device
  2. Causing the device to reload, resulting in a denial of service condition

This issue is particularly severe because it requires no authentication and can lead to complete device compromise. The attack vector requires only Layer 2 adjacency, making it exploitable by any attacker who can connect to the same network segment as the vulnerable phones.

Remediation

To address this vulnerability, network administrators should:

  1. Update affected Cisco IP Phones to the latest firmware versions that contain fixes for this vulnerability. Refer to the Cisco Security Advisory for specific version information.

  2. If immediate patching is not possible, consider these mitigations:

    • Disable CDP on IP Phones where feasible
    • Implement network segmentation to limit Layer 2 access to IP Phones
    • Monitor network traffic for suspicious CDP packets
    • Implement strict physical security controls to prevent unauthorized network access

  3. Verify successful remediation by checking firmware versions on all deployed IP Phones.

References

  1. Cisco Security Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200205-voip-phones-rce-dos
  2. Packet Storm Security: http://packetstormsecurity.com/files/156203/Cisco-Discovery-Protocol-CDP-Remote-Device-Takeover.html
  3. Common Weakness Enumeration: CWE-20 (Improper Input Validation)
  4. MITRE CVE: CVE-2020-3111

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

Focus on What Matters

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

Let's talk!

background