Jun 26 15:58:52 hostme su: pam_unix(su:session): session opened for user {USER} by root(uid=0)
Jun 26 15:59:02 hostme su: pam_unix(su:session): session opened for user {USER} by root(uid=0)
Jun 26 15:59:37 hostme su: pam_unix(su:session): session opened for user {USER} by root(uid=0)
Is that something to be worried about? Does this mean someone has shell?