Let me shoot a couple of scare tactics your way since scare tactics appear to be what drives some people to take fix malware problems free a little more seriously, or at the very least start considering the issue.
No software system is immune to vulnerabilities and bugs. Security holes will be found and guys will do their best to exploit them. Keeping your software up-to-date is a fantastic way to stave off attacks, once security holes are found, because their products will be fixed by reliable software vendors.
Harness Scanner goes through the files on your site database, comment and place tables seeking anything suspicious. Additionally, it informs you for plugin names. It description does not remove anything, it warns you.
You can extend the plugin features with premium plugins such as: Amazon S3 plugin, Members only plugin, DropShop etc.. So I think you can use it at no cost and this plugin is a good choice.
But realize that security is something you really need to start thinking about. Don't just be the type, consider steps to start protecting yourself have a peek at this site today. Do not let Joe the Hacker make your life miserable and turn all in creating come crashing down in a matter of moments that you've worked so hard.