Tools like TMAC (Technitium MAC Address Changer) are legitimate, safe, and can help with lighter bans.
If you don't want to pay for a premium service, these are the most reliable manual methods:
Updating or re-flashing your BIOS can sometimes reset the Motherboard ID that games track.
A full "Custom" reinstall of Windows, combined with wiping your drives, is often more effective than a sketchy .exe file. Verdict