A hacker has been abusing a serious vulnerability in old Windows machines that both Microsoft and the NSA have warned could lead to a computer virus outbreak.

Fortunately, the attacks have only involved installing a cryptocurrency miner, according(Opens in a new window) to Kevin Beaumont, the security researcher who noticed the activity over the weekend.

The vulnerability, dubbed BlueKeep, affects unpatched Windows 7, Vista, and XP machines, along with Windows Server 2003 and 2008 systems, that have the Remote Desktop Service feature activated. If exploited, you can basically take over the Windows machine to view, modify, or delete data,