There's a perception, says Gartner cloud security analyst Jay Heiser, that the most significant risk in using the cloud is that sensitive data can be leaked. But there's been little evidence of that, he says. Sony suffered a compromise of potentially tens of millions of customers in 2011 related to its cloud, and there have been a handful of other breaches of personally identifiable information being leaked from the cloud.
But more common nowadays are cloud outages and data loss, and Heiser says many enterprises are ill-prepared for those incidents.
Just look at some of the major outages from the past few years. Amazon Web Services, the market-leading cloud provider, has experienced three major outages in the past two years. After an April 2011 Elastic Compute Cloud (EC2) outage, some level of data was irrecoverable, Heisler says. Evernote lost the data of 6,000 customers in 2010 and Carbonite lost a portion of its customer's backups in 2009, he says."