I found these files in /etc/cron.daily directory.

gb-mint cron.daily # cat /home/gb/crackfile
total 60
-rwxr-xr-x 1 root root 311 Feb 19 2014 0anacron
-rwxr-xr-x 1 root root 15481 Apr 10 2014 apt
-rwxr-xr-x 1 root root 314 Feb 17 2014 aptitude
-rwxr-xr-x 1 root root 355 Jun 4 2013 bsdmainutils
-rwxr-xr-x 1 root root 384 Mar 23 2014 cracklib-runtime
-rwxr-xr-x 1 root root 256 Mar 7 2014 dpkg
-rwxr-xr-x 1 root root 372 Jan 22 2014 logrotate
-rwxr-xr-x 1 root root 1261 Sep 23 2014 man-db
-rwxr-xr-x 1 root root 435 Jun 20 2013 mlocate
-rwxr-xr-x 1 root root 249 Feb 16 2014 passwd
-rwxr-xr-x 1 root root 383 Aug 1 2014 samba
-rwxr-xr-x 1 root root 328 Jul 18 2014 upstart

Have I been hacked?

Where did cracklib-runtime come from?
I am running Linux Mint 17.1.