This file contains the logs of all the attempts made for login to your machine

less /var/log/secure
Oct 16 18:01:12 localhost unix_chkpwd[3503]: password check failed for user (deepak)
Oct 16 18:01:14 localhost sshd[3501]: Failed password for deepak from 10.10.10.30 port 2326 ssh2
Oct 16 18:01:21 localhost passwd: pam_unix(passwd:chauthtok): password changed for deepak
Oct 16 18:01:21 localhost passwd: gkr-pam: couldn’t update the ‘login’ keyring password: no old password was entered
Oct 16 18:01:24 localhost sshd[3501]: Accepted password for deepak from 10.10.10.30 port 2326 ssh2
Oct 16 18:01:24 localhost sshd[3501]: pam_unix(sshd:session): session opened for user deepak by (uid=0)
Oct 16 18:01:31 localhost sshd[3501]: pam_unix(sshd:session): session closed for user deepak