(Basic) Guestbook Hacked. Any solutions?

My guestbook.html file suddenly was wiped to 0K.

There is no possible explanation I can think of (I am the only administrator, and it's a solid password; the server had no problems) besides that it was hacked.

Is this possible? Could a hacker wipe the file to 0? If so, is there something I can do to prevent this ever happening again? We lost every one of our guestbook entries.

Thank you.

Are we talking advanced guestbook 1.5 or 2.3.x?

It may be worth speaking to your hosts to see if they did any work or moved your site to a new server as sometimes files get corrupted during transfers.

The old, basic guestbook - not the advanced one.

It wasn't the server - they didnt do any maintenance - and none of my other files (there are many) were affected in any way - I actually went through and checked every one to see if any other damage had occurred.

Only the guestbook.html file, and I think also the page_id.txt file that keeps track of the # of the entries.