On June 24, 2021, Microsoft announced Windows 11 will soon be released. Windows 11 is a major upgrade of the Windows NT operating system, which will be the successor to Windows 10. Such a major release doesn’t happen that often – Windows 10 was released in 2015 – so there has been a lot of interest in the new operating system. The new Windows version is due for public release at the end of 2021, but there is an opportunity to get an early copy for free.
On June 28, Microsoft revealed the first Insider Preview of Windows 11. Upgrading to the new Windows version is straightforward. For a lucky few (or unlucky few if Windows 11 turns out to be exceptionally buggy), an upgrade just requires a user to enroll in the Dev channel of the Windows Insider Program. That said, many people have been trying to get an upgrade from unofficial sources.
Unsurprisingly, unofficial ISOs that claim to provide Windows 11 do not. Instead, they deliver malware. Threat actors have been distributing these fake Windows 11 installers and using them to deliver a wide range of malicious payloads. At best, these fake Windows 11 installers will deliver adware or unwanted programs. More likely, malware will be installed with various degrees of maliciousness, such as Remote Access Trojans and backdoors that give the attackers full access to the victims’ devices, information stealers such as keyloggers that steal passwords and other sensitive data, cryptocurrency miners, and ransomware.
Researchers at Kaspersky Lab have identified several fake Windows 11 installers doing the rounds, including one seemingly legitimate installer named 86307_windows 11 build 21996.1 x64 + activator.exe. Despite the name and 1.76GB file size, it was not what it seemed. If the user executed the file and agreed to the terms and conditions, the file would proceed to download a different executable that delivers a range of malicious software onto the user’s device.
As the hype builds ahead of the official release date, we can expect there to be many other fake installers released. Hackers do love a major software release, as its easy to get users to double click on executable files. Malicious adverts, websites, and emails offering free copies of Windows 11 will increase, so beware.
Ensure you have an advanced and effective spam filtering solution such as SpamTitan in place to protect against malicious emails, and a web filter such as WebTitan installed to block malicious file downloads. You should also make sure that you only install software or applications from official sources and take care to ensure that you really are on the official website of the software developer before downloading any files. A double click on a malicious executable file could cause a great deal of pain and expense for you and your employer.