History of IP addresses that accessed a server via ssh

It has come to my attention that a server of mine has been hacked and infected with a known Chinese botnet. It was a prototype/testing virtual machine with its own static IP(US address) so no harm was caused(just took me a while to figure it out). Now I would like to know what IP/s was used for the intrusion to know if the attack originated from china. Is there a way to view a history of received connections on ssh on the server? Edit: The system is Linux Debian 7