In a new BitRAT malware distribution campaign discovered by researchers at AhnLab, threat actors are distributing the malware as a Windows 10 Pro license activator on webhards.
Webhards are online storage services popular in South Korea that have a steady influx of visitors from direct download links posted on social media platforms or Discord.
Due to their wide use in the region, threat actors are now more commonly using webhards to distribute malware.
The actor behind the new BitRAT campaign appears to be Korean based on some of the Korean characters in the code snippets and the manner of its distribution.
To properly use Windows 10, you need to purchase and activate a license with Microsoft.
While there are ways to get Windows 10 for free, you still need a valid Windows 7 license to get the free upgrade.
Those who do not want to deal with licensing issues or do not have a license to upgrade commonly turn to pirating Windows 10 and using unofficial activators, many of which contain malware.
In this campaign, the malicious file promoted as a Windows 10 activator is named ‘W10DigitalActiviation.exe’ and features a simple GUI with a button to “Activate Windows 10.”
However, instead of activating the Windows license on the host system, the “activator” will download malware from a hardcoded command and control server operated by the threat actors.
The fetched payload is BitRAT, installed in %TEMP% as ‘Software_Reporter_Tool.exe’ and added to the Startup folder. The downloader also adds exclusions for Windows Defender to ensure that BitRAT won’t encounter detection issues.
Once the malware installation process is completed, the downloader deletes itself from the system leaving behind only BitRAT.