Apache Error Log shows the following messages. Seems like an attack to me But not sure what it means. Can anyone tell me what are these attacks and how to prevent any damage from such attacks
[Wed Jan 22 00:39:36 2014] [error] [client x.y.z.a] File does not exist: /var/www/site/webdav
[Wed Jan 22 00:39:36 2014] [error] [client x.y.z.a] File does not exist: /var/www/site/administrator
[Wed Jan 22 00:39:37 2014] [error] [client x.y.z.a] File does not exist: /var/www/site/wp-login.php
[Wed Jan 22 00:39:37 2014] [error] [client x.y.z.a] File does not exist: /var/www/site/blog
[Wed Jan 22 00:39:37 2014] [error] [client x.y.z.a] File does not exist: /var/www/site/zecmd
[Wed Jan 22 00:39:37 2014] [error] [client x.y.z.a] File does not exist: /var/www/site/web-console
[Wed Jan 22 00:39:38 2014] [error] [client x.y.z.a] File does not exist: /var/www/site/manager
[Wed Jan 22 11:18:19 2014] [error] [client x.y.z.a] script not found or unable to stat: /usr/lib/cgi-bin/php
[Wed Jan 22 11:18:19 2014] [error] [client x.y.z.a] script not found or unable to stat: /usr/lib/cgi-bin/php5
[Wed Jan 22 11:18:19 2014] [error] [client x.y.z.a] script not found or unable to stat: /usr/lib/cgi-bin/php-cgi
[Wed Jan 22 11:18:19 2014] [error] [client x.y.z.a] script not found or unable to stat: /usr/lib/cgi-bin/php.cgi
[Wed Jan 22 11:18:19 2014] [error] [client x.y.z.a] script not found or unable to stat: /usr/lib/cgi-bin/php4