If you are unable to access your WHM due to cphulk. you may still be able to SSH to your server. Once you are login into your server as a root use the following commands to disable cPHulk:
/usr/local/cpanel/etc/init/stopcphulkd /usr/local/cpanel/bin/cphulk_pam_ctl --disable
After these steps if cPanel will be restarted, cPhulkd will be on.