Magento has acquired the reputation for being a robust and secure e-commerce development platform. However, it is not indomitable and Magento stores still do get hacked. To begin with, you need to establish that the Magento store has actually been compromised. Here are some ways to identify the hacking issue: Customers are reporting strange credit card activities, The store has been suspended by the Magento Hosting partner on account of malicious activities.Read more....http://www.magentous.com/blog/how-to-address-magento-store-hacked/