CVE-2020-9885:Apple iMessage Tapbacks Vulnerability Allows Removed Users to Rejoin Groups (CVE-2020-9885)

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CVE-2020-9885 addresses a security vulnerability in Apple's iMessage service related to the handling of tapbacks (reaction emojis). The flaw allowed users who had been removed from an iMessage group chat to rejoin the group without permission. This issue was classified as CWE-345 (Insufficient Verification of Data Authenticity) and affected multiple Apple operating systems including iOS, iPadOS, macOS, tvOS, and watchOS. Apple resolved the vulnerability by implementing additional verification measures in their messaging platform.

Overview

This vulnerability in Apple's iMessage service stems from improper handling of tapbacks, which are the reaction emojis users can add to messages. When a user was removed from an iMessage group chat, they could exploit this vulnerability to rejoin the group without invitation or authorization from the group administrator. This represents a security issue as it undermines the access control mechanisms intended to manage group membership. The vulnerability could potentially be used for harassment, unauthorized access to conversations, or to obtain information shared within groups after a user's removal. The issue affects multiple Apple operating systems including iOS and iPadOS prior to version 13.6, macOS Catalina prior to 10.15.6, tvOS prior to 13.4.8, and watchOS prior to 6.2.8.

Remediation

To address this vulnerability, users should update their Apple devices to the following versions or later:

  • iOS and iPadOS: Update to version 13.6 or later
  • macOS Catalina: Update to version 10.15.6 or later
  • tvOS: Update to version 13.4.8 or later
  • watchOS: Update to version 6.2.8 or later

These updates include additional verification mechanisms for iMessage tapbacks that prevent removed users from rejoining group conversations without proper authorization. To update your device:

  • iOS/iPadOS: Go to Settings > General > Software Update
  • macOS: Go to System Preferences > Software Update
  • tvOS: Go to Settings > System > Software Updates
  • watchOS: Use the Watch app on your paired iPhone to install updates

References

  1. Apple Security Updates for iOS and iPadOS 13.6: https://support.apple.com/HT211288
  2. Apple Security Updates for macOS Catalina 10.15.6: https://support.apple.com/HT211289
  3. Apple Security Updates for tvOS 13.4.8: https://support.apple.com/HT211290
  4. Apple Security Updates for watchOS 6.2.8: https://support.apple.com/HT211291
  5. Common Weakness Enumeration: CWE-345 (Insufficient Verification of Data Authenticity): https://cwe.mitre.org/data/definitions/345.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. Health Care & Social Assistance
    Health Care & Social Assistance
  2. Educational Services
    Educational Services
  3. Public Administration
    Public Administration
  4. Accommodation & Food Services
    Accommodation & Food Services
  5. Administrative, Support, Waste Management & Remediation Services
    Administrative, Support, Waste Management & Remediation Services
  6. Agriculture, Forestry Fishing & Hunting
    Agriculture, Forestry Fishing & Hunting
  7. Arts, Entertainment & Recreation
    Arts, Entertainment & Recreation
  8. Construction
    Construction
  9. Finance and Insurance
    Finance and Insurance
  10. Information
    Information
  11. Management of Companies & Enterprises
    Management of Companies & Enterprises
  12. Manufacturing
    Manufacturing
  13. Mining
    Mining
  14. Other Services (except Public Administration)
    Other Services (except Public Administration)
  15. Professional, Scientific, & Technical Services
    Professional, Scientific, & Technical Services
  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

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