Magento has released the following critical security announcement:

https://magento.com/security/news/important-security-update

In light of the concerns raised in this alert, we advise all store owners to:

1. Confirm that your Magento install is running the latest version and that all security patches have been installed.
2. Test the site on https://www.magereport.com to identify any potential vulnerabilities.
3. Run a diff comparison of core Magento files against a freshly downloaded copy to see if there are any modified or extra files.

Please contact Reliable Penguin if you need assistance with any of these tasks.