What you need to know about the biggest hack of the US government in years

Russian agents are suspected in the Orion breach, which affected the treasury and commerce departments - and perhaps others

A vast trove of US government emails has been targeted in a hack thought to have been carried out by Russia, American officials revealed on Monday.

The stunningly large and sophisticated operation reportedly targeted federal government networks and marks the biggest cyber-raid against US officials in years. The treasury and commerce departments were both affected and others may have been breached.