Hi,
My server has been attacked by some one came from FiOS of verizon. Attacker's scripts ate up my CPUs' usage for hours. And maybe some backdoors were opened 
last logging info:
Last login: Tue Aug 19 00:29:19 2014 from static-100-32-93-59.lsanca.fios.verizon.net
(time above is the local time of my area: UTC+8)
BTW, verizon's support SUCKS! I can't even find a email address for me to complain.
Thx.