CVE-2021-39783:Privilege escalation vulnerability in Android's rcsservice allows local attackers to modify TTY mode due to missing permission checks.

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CVE-2021-39783 affects Android's rcsservice component. The vulnerability stems from a missing permission check that allows unauthorized modification of TTY (TeleTYpe) mode settings. This could be exploited by a local attacker to gain elevated privileges on the device without requiring additional execution privileges. The vulnerability was identified in Android 12L and assigned Android ID A-197960597. No user interaction is required for successful exploitation, making this a significant security concern for affected devices.

Overview

This vulnerability (CVE-2021-39783) is classified as CWE-269 (Improper Privilege Management) affecting Android's Rich Communication Services (RCS) implementation. The issue exists in the rcsservice component where a missing permission check allows unauthorized modification of TTY mode settings. TTY mode is typically used for accessibility purposes to assist users with hearing or speech disabilities. By exploiting this vulnerability, a local attacker could potentially escalate privileges on the device, potentially gaining access to sensitive functions or data that should be restricted. The vulnerability affects Android 12L and requires no user interaction for exploitation, making it a serious security risk that could be leveraged in targeted attacks.

Remediation

To address this vulnerability, users should:

  1. Update to the latest version of Android that contains the security patch for this issue.
  2. Install all security updates provided by Google through the Android Security Bulletin.
  3. Ensure devices are configured to automatically download and install security updates.
  4. For enterprise environments, IT administrators should prioritize the deployment of this patch to all managed Android 12L devices.
  5. Until patched, minimize the installation of applications from untrusted sources to reduce the risk of exploitation.
  6. Monitor for unusual system behavior that might indicate compromise.

References

  1. Android Security Bulletin for Android 12L: https://source.android.com/security/bulletin/android-12l
  2. Common Weakness Enumeration (CWE-269): Improper Privilege Management
  3. Android Security Updates page: https://source.android.com/security/bulletin/
  4. Android ID: A-197960597

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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