When you see the dreaded Google attack site warning, you should immediately email : hostmaster [@] centriohost.com. Be sure to include your domain name because we will need to locate the virus that caused the issue and take steps to secure your account.
Once the account has been cleaned and secured, please request a delisting through your Google Webmaster account. This is not something that CentrioHost can do for you. The excerpt below was copied from Google, and gives you step by step instructions to request a delisting.
Once you have reviewed your site and are sure it is clean, you can can submit a request for review. Note, you will need to verify site ownership before you can request a site review.