Database config file lost credentials on its own 1.7.6

[Dan1]

Very strange happening today. Last night my shop site 1.7.6 was working perfectly, today the site could not be accessed, error page pops up "can't connect to database".

So I checked the config file at app/config/parameters.php and all the values for database connection were replaced, password was blank, user name was "root", database name was shortened to one word out of the 3 that make up the full database name.

I edited the file with the correct credentials and site is working fine.

I'm worried that I got hacked, or the file got corrupted somehow. Any ideas?