The fix malware problem Codex has an outline of what permissions are okay. File and directory permissions can be changed either via an FTP client or within the page from the hosting company.
Also, don't make the mistake of believing that your hosting company will have your back as far as WordPress copies go. Not always. While they say they do, our website it has been my experience that the company may or may not be doing backups. Why take that kind of chance?
Keep your WordPress Setup wikipedia reference to date - One of the easiest and most valuable tasks you can do yourself is to make sure your WordPress installation is updated. WordPress provides you a notice in your dashboard, so there is really no reason to not do this.
Another step to take to make WordPress more secure is to always upgrade WordPress to the latest version. The main reason behind this is that there also come fixes for security holes making it essential to upgrade early.
Bear in mind that the safety of your sites depend on how you manage them. Be certain that you follow these simple strategies to prevent hacks and exploits on sites and your useful link blogs.