I'm not adding this support thread to say wp-db-backup is the problem of the recurring hacks - I'd like to know if anyone has had the same issues. We use this plugin on all of our sites. The hacks have been slightly different from site to site, but the ones that we continue to have issues with return like clockwork on the scheduled cron job for running the database backup.
A couple months ago, we found two sites that actually had the hack in the wp-options table under the cron job for wp-db-backup. Since then, hacks have increased (several different types) on many sites on different hosting companies.
So far, the only thing all sites have had in common is this plugin. So I would like to know if anyone else has had similar problems in the past couple months.
Thanks much for any input.