Allot of people server owners think that there is not much that they can do to once they „secure“ their website or server,and that is absolutely not true.There are many simple things that you can do every day to make sure you are safe.
First thing that website owners can do is what i mentioned in previous part and that is to watch for new files not created by them and files that are modified recently.You can do search for all files and folders and sort them by date created and later by modification date so you see modified and new created files on top.This is kinda hard to do manually for server owners who have shared hosting with allot of websites on.But lucky for them there are many scripts on internet that will watch activity on server and send instant email is something not allowed is going on.
Next thing is to keep all of your software and scripts up to date.If possible turn on automatic update if that feature is available.Old and outdated software is one of the main reason why websites and servers are getting hacked,So don't be lazy to check if there is update available for some of your scripts unless automatic update is enabled
One more thing that will give you additional safety is to check for last ip used to login for administrator.Whenever you login to admin panel check the last used ip.If its not yours than you have unwanted quests.And best thing to do in that case is first to change your password.and examine all files after changing the password.Also u should do the database backup and reinstall your scripts since there is a possibility that attacker modified some of the scripts to have backdoor for later access when you change your password.Simple thing to do but will give u a clue if anyone besides you have been logged on admin panel or cpanel.
If your website allows attachments or file uploads check new ones daily.Look for php scripts images with large file size since if php upload is not allowed they will try to upload scripts and backdoors as images (mostly large gif files ).Safe way to see if image is actually image or some php script is to try opening it.For scrips it will say something like broken image or something similar but it won't show image for sure.If you see image like that make 100% if its image or not since in some cases it could really be what it says it is broken image.After you find broken image download it and open with notepad or wordpad.It will show you the source so you can look if there are any php codes inside that image,in case of confirmation that its script and not image delete it and do prevention mentioned in previous parts of this course.
All things described above will take aprox 10-20 minutes of your time at first but when it became routine it will take like 5 minutes or less.Just don't be lazy to do them.Am saying this because its in people's nature to be lazy and in lot of cases that cost them allot.