Nearly nine in 10 executives and employees are using their personal smartphones or tablets for business and about half are doing so without the permission of their companies, a new study shows.Making the situation even more precarious, less than half of the more than 4,000 mobile device users surveyed by Juniper Networks in the U.S., U.K., Germany, China and Japan took even the most basic precautions in using mobile applications.The findings, released this week, point to the need for all C-level executives to start taking mobile security seriously to avoid giving hackers an open door to the corporate network."You're extremely hard pressed to find an enterprise that says, 'Yes, we understand what's going on with mobility, we did our research and we put together and have implemented a comprehensive solution to address our mobility concerns,'" Dan Hoffman, chief mobile security evangelist for Juniper, said Friday. "They're just not there right now."[See also:\u00a0Mobile BYOD users want more security]As a security vendor, Juniper has a vested interest in scaring the bejeezus out of execs to get them to spend their company's money on expensive security technology to lockdown mobile devices. Nevertheless, based on the study, there are some troubling trends within the enterprise.Juniper found that 89% of business users, often called prosumers, are using their personal devices to access what the vendor says is "critical work information." More than 40% of that group is using their tablets and smartphones without asking their companies for permission.This risky behavior has already had some consequences. Nearly a third of IT managers have reported a security threat as a result of personal devices accessing company data, Juniper said. In China, that number doubles.The fact that breaches have occurred is unsurprising, given the lack of commonsense in the use of mobile apps. Less than half of the respondents said they read the terms and conditions before downloading an app, manually set data security features and settings or researched applications to ensure they are trustworthy.In the background to all this risky behavior is a growing malware threat. In 2011, the number of malware targeting mobile devices grew 155% year to year, according to Juniper. In the first three months of this year, the number has grown by an additional 30%.Most troubling about the increase this year is the rise is spyware capable of stealing personal, financial and work information. Juniper found the number of spyware doubled in the first quarter.The report had a bright side. Many people are willing to have their devices supported by IT staff, which would give their companies the needed control to secure the devices. The study found that more than four in 10 employees and execs are actually pressuring IT staff for support. Hoffman recommends CSOs give these employees and execs what they want."Providing security to the bring-your-own-device (BYOD) user has to be about protecting the enterprise, but I think it also has be about protecting the end user because fundamentally, they're the same," Hoffman said.