They might install software containing a virus or trojan.
One company got all of its files encrpypted by Ransomware because one kid installed a contaminated game.
It only took 4 hours for all company files to be encrypted. Various cybersecurity firms are showing an average 2500% increase in phishing campaigns and a 700% increase in attacks directly related to work from home individuals.
Avoid being part of those stats!
Once again: PREVENTION