I don't believe it happened in this case, but you can in fact hack anything that has a means of external connection. That's how Stuxnet got to its target.
BELIEVES RUSSIA HACKED VOTING MACHINES THAT WEREN'T CONNECTED TO THE INTERNET; BUT THE IDEA THAT MILLIONS OF ILLEGAL IMMIGRANTS VOTED FOR HILLARY CLINTON IN STATES THAT DON'T REQUIRE VOTER ID IS ABSURD AND RIDICULOUS