Make sure you're downloading software from trusted sources. There have been reports of some miners possibly including malware, whilst this isn't confirmed it's down to you to exercise caution installing anything on your machines. The GitHub links to Ravencoin, MSFTserver and Brian's miners have been used by lots in the community and are generally trusted. Malware comes in different forms [https://blog.talosintelligence.com/2018/04/cryptomining-campaign-returns-coal-not-diamond.html cryptomining campaign returns coal not diamond].