The Department of Homeland Security's Cybersecurity and Infrastructure Security Agency.  They have a wealth of information with regards to telecommuting and protecting businesses.

www.cisa.gov/coronavirus

The IT training/awareness videos:

https://www.fbi.gov/investigate/counterintelligence/foreign-influence/protected-voices

If you were a victim of a teleconference hijacking, or any cyber-crime for that matter, report it to the FBI’s Internet Crime Complaint Center at ic3.gov. Additionally, if you receive a specific threat during a teleconference, please report it to us at tips.fbi.gov or call the FBI San Diego Division at (858) 320-1800