CVE-2021-24077 · Windows Fax Service Remote Code Execution Vulnerability

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.

The following workaround might be helpful in your situation. In all cases, Microsoft strongly recommends that you install the updates for this vulnerability as soon as possible even if you plan to leave this workaround in place: Uninstall the Windows Fax and Scan feature Click Start, click Settings or Control Panel depending on your version of Windows. For Windows 7 and 8.1, select Programs. For Windows 10, select Apps. Select Turn Windows features on or off on Windows 7 and 8.1. Select Optional Features on Windows 10. Uncheck the Windows Fax and Scan feature. Restart the computer. Impact of Workaround Removing the Windows Fax and Scan service will prevent the computer from sending or receiving faxes. How to undo the workaround Follow the preceding steps, but check the box next to Windows Fax and Scan in step 4.