I took a few minutes to look at traffic on one of my bigger sites and noticed a huge increase in my 404 traffic on that site. 404's are already double this month what they were last month, that raised a red flag

.
So I checked it out. the SE's still list around 20 pages that no longer exist, and that is my normal 404 traffic. Nothing to care about at all.
Then I found these urls that do not and never have existed:
Required but not found URLs (HTTP code 404):
/krheupfile_flash.asp
/suozftp.rar
/srestmdqq.asp
/arknmirserver.rar
/xmwywebeditor/ewebeditor.asp
/pjhkplus/infosearch.php
What do you guys make of it? Hacking attempt? Thats my thought, but whats more is i've never been proactive in stopping anything like this beyond going with a decent host.
Anything I can do to safeguard myself from a low level attempt such as this?
Thanks in advance.