Check the logs:
# nano /var/log messages PAM-hulk[13813]: Brute force detection active: 580 LOGIN DENIED
Check
cphulkd.log at /usr/local/cpanel/logs
# nano /usr/local/cpanel/logs/login_log 72.177.xxx.xx - root [11/04/2014:05:48:13 -0000] "POST /login/?login_only=1 HTTP/1.1" DEFERRED LOGIN whostmgrd: brute force attempt (user root) has locked out IP 72.177.xxx.xx