In many cases you may not even be aware that you've been hacked until its too late and...
- your hosting company shuts you down for sending spam,
- you are unable to access the backend of your site
- your google search results are being redirected elsewhere
- you received an email from google webmaster tools that your site is delisted from google
- your homepage is defaced
It is essential to quickly make a backup of your site (even with infected files) as many hosting companies will not quarantine your website but delete it altogether.
* restore your site from recent backup and secure your site or
* manually go through the code of your website, remove and clean offending files and scan your site with antivirus
I will also provide you with a report on how I suspect the hack was perpetrated, the files or offending plugins that were hacked, and recommend safe alternatives to the plugins/themes that were hacked.
As an extra, after everything is restored I will then install some primary security measures to ensure that the site is safe from attacks in the future.