Unofficial Windows 11 upgrade installs info-stealing malware

LASER_oneXM

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Hackers are luring unsuspecting users with a fake Windows 11 upgrade that comes with malware that steals browser data and cryptocurrency wallets.
The campaign is currently active and relies on poisoning search results to push a website mimicking Microsoft's promotional page for Windows 11, to offer the information stealer.


Microsoft offers an upgrade tool for users to check if their machine supports the latest operating system (OS) from the company. One requirement is support for Trusted Platform Module (TPM) version 2.0, which is present on machines that not older than four years.

The hackers are preying on users that jump at installing Windows 11 without spending the time to learn that the OS needs to meet certain specifications.
The malicious website offering the fake Windows 11 is still up at the time of writing. It features the official Microsoft logos, favicons, and an inviting “Download Now” button.

Infection process​

According to CloudSEK, the threat actors behind this campaign are using a new malware that researchers named “Inno Stealer” due to its use of the Inno Setup Windows installer.
The researchers say that Inno Stealer doesn’t have any code similarities to commodity other info-stealers currently in circulation and they have not found evidence of the malware being uploaded to the Virus Total scanning platform.

The loader file (Delphi-based) is the “Windows 11 setup” executable contained in the ISO, which, when launched, dumps a temporary file named is-PN131.tmp and creates another .TMP file where the loader writes 3,078KB of data.