Data-destruction policies in the age of cloud computing

These days, most big companies and many midsize ones have some form of a data-governance program, typically including policies for data retention and destruction. They have become an imperative because of increasing attacks on customer data and also state and national laws mandating protection of customer data. The old mind set of “Keep everything, forever” has changed to “If you don’t have it, you can’t breach it.”

In some ways, managing data-retention policies has never been easier to implement in the cloud. Cloud vendors often have easy templates and click-box settings to retain your data for a specific period and then either move it to quasi-offline cold digital storage or straight to the bit bucket (deletion). Just click, configure, and move on to the next information security priority.

Just Click Delete?

However, I’m going to ask an awkward question, one that has been burning in my mind for a while. What really happens to that data once you click “delete” on a cloud service? In the on-premises, hardware world, we all know the answer; it would simply be deregistered on the disk it resides on. The “deleted” data still sits on the hard drive, gone from the operating system view and waiting to be overwritten when the space is needed. To truly erase it, extra steps or special software are needed to overwrite the bits with random zeros and ones. In some cases, this needs to be done multiple times to truly wipe out the phantom electronic traces of the deleted data.

And if you do business with the US government or other regulated entities, you may be required to comply with Department of Defense standard 5220.22-M, which contains specifics on data destruction requirements for contractors. These practices are common, even if not required by regulations. You don’t want data you don’t need any more coming back to haunt you in the event of a breach. The breach of the Twitch game-streaming service, in which hackers were able to gain access to basically all of its data going back almost to the inception of the company — including income and other personal details about its well-paid streaming clients — is a cautionary tale here, along with reports of other breaches of abandoned or orphaned data files in the last few years.

Lack of Access to Verify

So, while the policies are easier to set and manage in most cloud services versus on-premises servers, assuring it is properly done to the DoD standard is much harder or impossible on cloud services. How do you do a low-level disk overwrite of data on cloud infrastructure where you don’t have physical access to the underlying hardware? The answer is that you can’t, at least not the way we used to do it — with software utilities or outright destruction of the physical disk drive.

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