Access to test builds of Windows through Windows Insider Program channel has been used by cybercriminals. According to Kaspersky, more and more people are downloading and installing application posing to be Windows 11 installer, which in fact is a camouflaged malware.

According to Kaspersky’s malware experts, it contains a file which matches the size of Windows 11 installer - 1.75GB and name matches the actual Windows 11 build number 86307_windows 11 build 21996.1 x64 + activator.exe. However, there is one but - the file contains a single DLL file that is tasked with downloading another file. This file then displays the “License Agreement” dialog box where in its summary you can read that “sponsored applications” will be installed on the computer. If the agreement is accepted, malware will be installed on the device.

According to Kaspersky, the payload is changed dynamically and it can range from programs that display ads, as well as Trojan horses or applications that steal login credentials.
If you want to test Windows 11 be sure to use a reliable source.