Unauthorised access

[rincewind]

Hi,
Is there any way for someone to access your web site server and change files without your permission.
I ask because I am working on a trucker site and the main page contains certain adds. Today the adds were replaced by other trucker adds without my permission (or the permission of any one else in the company). The page code affected consists of javascript (to preload and rotate the images) and the a html table which creates the layout for the adds. Only the html code was changed, the javascript was not. The original adds were not deleted from the server, the new adds were just added to the folder and the page code changed.
Aswell as the code pointing to the images being changed, the following code was added just before the </body> tag
<p>
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<!--webbot bot="HitCounter" b-reset="TRUE" u-custom i-image="4" i-resetvalue="42589" PREVIEW="&lt;strong&gt;[Hit Counter]&lt;/strong&gt;" i-digits="6" startspan --><strong>[Hit Counter]</strong><!--webbot bot="HitCounter" endspan i-checksum="10367" --></p>
-------------------------------------------------------

Has anyone encountered this before and more importantly how do I prevent it from happening again?
Thanks

[PeOfEo]

are you hosting yourself or are you on a webfarm's server.

[rincewind]

I use the services of a web hosting company (interland).
They control the server, i simply upload/change files.
Does that answer your question?

[PeOfEo]

well you really need to take it up with them then because if its professional servers and they have a good firewall and all that good stuff they should have any leaks patched up. Could be that your pass was cracked.

[rincewind]

will do thanks, I just wanted to check if anyone new of anything I could do to stop it but I'll get the server tech support people on it,
thanks for the help

[Ribeyed]

hi,
long shot here, but if host is using IIS and its not locked down, maybe the ftp was set to allow annonomous users. Maybe just by entering ftp.yourwebsite.com they gained access.

[rincewind]

Thanks for the idea but i tried it and it won't allow anonymous logins