"You can access not just one company's data but credit card files from hundreds of companies," he said.
Dave Malcom, chief information security officer of Hyatt Hotels, said he's keenly aware that employees use consumer-grade cloud storage services with their mobile devices -- and it's an issue he's already addressing.
He said, for instance, that employees often use the same passwords for multiple systems, including their own devices and web services. That means if an online cloud storage service is hacked, Hyatt's email system could well be at risk, too.
The hotel chain is now surveying employee workstations to find out whether cloud storage apps such as Dropbox have been downloaded and what kind of information is being stored.
"Obviously, that means there's probably a corresponding machine they're placing documents on that we don't own," Malcom said. "We're starting to try to get in front of it. Then we're trying to provide them with a corporately blessed service.
"Obviously, it becomes a lot more challenging with devices we don't own," he added.
Cloud content sharing service SkyDox released a survey on Thursday that shows more than half of all employees leave their IT departments in the dark about the free file-sharing platforms they use to upload corporate documents. The survey of more than 4,000 employees was conducted from April 16-30, and it showed that 77 percent of employees require access to work documents outside of their office - especially those who work in financial services (89 percent), professional services (96 percent) and healthcare (70 percent).
To enable that access, 66 percent of employees are using a free file-sharing platform to store or share corporate documents. That percentage spiking to 87 percent for those in professional services and 84 percent for those in financial services.
Of those using file-sharing platforms, 55 percent do not notify their IT department of the file-sharing platforms they use. For some workers, that number is greater. For instance, 71 percent of employees in sales withhold information from IT, compared to 5 percent of respondents who work in financial positions.
The survey also revealed that 80 percent of respondents use their own mobile devices for work. Those who work in professional services (92 percent), financial services (86 percent) and healthcare (84 percent) are most likely to embrace BYOD habits, with creative services (60 percent) and government sectors (39 percent) lagging.
A major reason employees use consumer services to store business data is because there's no alternative offered by the company.
"You can use mobile device management platforms to help lock these applications down," Malcom said. "The other thing is, and this is more effective, [give] employees the applications you've blessed to do that. Some organizations are aggressive at rolling out Box.net so people don't use EverNotes and Dropbox, which are considered less secure."
When it comes to bringing your own devices to work, Hyatt Hotels has strict policies. For example, the company requires all employees to register mobile devices and it makes no bones about the fact that it will remotely wipe all data on any device that is lost or stolen. And, no confidential data can be stored outside of the corporate firewall.
Of course, if the data is being backed up onto a cloud service, that will require new policies and technology, he said.