为什么会被hack?

leomaster

我在一个网站看见
”Warning Warning: I am able to write to the configuration file: /home/XXXXXXX/public_html/XXXXXX/includes/configure.php. This is a potential security risk - please set the right user permissions on this file.“

请问这是不是被hack?

我客户的网站之前发生过一些folder里的file全被delete.

hacker是怎样attack的？通过网站就行了吗？