CVE-2021-1722: Windows Fax Service Remote Code Execution Vulnerability

Overview

Severity
High (CVSS 8.1)
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Category
Remote Code Execution
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2021-Feb
Released
2021-02-09
EPSS Score
8.46% (percentile: 92.4%)

FAQ

In what scenarios is my computer vulnerable? For Windows 11 and Windows 10 the FAX service is not installed by default. For the vulnerability to be exploitable, the Windows Fax and Scan feature needs to be enabled, and the Fax service needs to be running. Systems that do not have the Fax service running are not vulnerable. How can I verify whether the Fax service is running? Hold the Windows key and press R on your keyboard. This will open the Run dialog. Type services.msc and press Enter to open the Services window. Scroll through the list and locate the Fax service. If the Fax service is not listed, Windows Fax and Scan is not enabled and the system is not vulnerable. If the Fax service is listed but the status is not Running, then the system is not vulnerable at the time, but could be targeted if the service was started. The update should be installed as soon as possible or the Fax service should be removed if not needed.

Affected Products (40)

Windows

  • Windows 10 Version 1803 for 32-bit Systems
  • Windows 10 Version 1803 for x64-based Systems
  • Windows 10 Version 1803 for ARM64-based Systems
  • Windows 10 Version 1809 for 32-bit Systems
  • Windows 10 Version 1809 for x64-based Systems
  • Windows 10 Version 1809 for ARM64-based Systems
  • Windows Server 2019
  • Windows Server 2019 (Server Core installation)
  • Windows 10 Version 1909 for 32-bit Systems
  • Windows 10 Version 1909 for x64-based Systems
  • Windows 10 Version 1909 for ARM64-based Systems
  • Windows Server, version 1909 (Server Core installation)
  • Windows 10 Version 2004 for 32-bit Systems
  • Windows 10 Version 2004 for ARM64-based Systems
  • Windows 10 Version 2004 for x64-based Systems
  • Windows Server, version 2004 (Server Core installation)
  • Windows 10 Version 20H2 for 32-bit Systems
  • Windows 10 Version 20H2 for ARM64-based Systems
  • Windows Server, version 20H2 (Server Core Installation)
  • Windows 10 for 32-bit Systems
  • Windows 10 for x64-based Systems
  • Windows 10 Version 1607 for 32-bit Systems
  • Windows 10 Version 1607 for x64-based Systems
  • Windows Server 2016
  • Windows Server 2016 (Server Core installation)
  • Windows 8.1 for 32-bit systems
  • Windows 8.1 for x64-based systems
  • Windows RT 8.1

ESU

  • Windows 7 for 32-bit Systems Service Pack 1
  • Windows 7 for x64-based Systems Service Pack 1
  • Windows Server 2008 for 32-bit Systems Service Pack 2
  • Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
  • Windows Server 2008 for x64-based Systems Service Pack 2
  • Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
  • Windows Server 2008 R2 for x64-based Systems Service Pack 1
  • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
  • Windows Server 2012
  • Windows Server 2012 (Server Core installation)
  • Windows Server 2012 R2
  • Windows Server 2012 R2 (Server Core installation)

Security Updates (14)

Acknowledgments

Xuefeng Li (<a href="https://twitter.com/lxf02942370">@lxf02942370</a>) of <a href="https://www.sangfor.com/">Sangfor</a> & Zhiniang Peng (<a href="https://twitter.com/edwardzpeng">@edwardzpeng</a>)

Revision History

  • 2021-02-09: Information published.