The gang entered the house in Hampton Crescent in Larne at around 1.35 am this morning.
They brutally attacked the occupant with baseball bats and bars.
He suffered fractures to his arm and leg.
Local loyalist paramilitaries are a focus of police inquiries.
Police said a number of other people who were in the property at the time were not hurt.
Detectives have appealed for anyone with information to contact them on the 101 non-emergency number.