Do you really know who or where your employees are and what they're doing on your network?

Studies continue to show that one of the largest threats to data security in small businesses is from employees.

In a study by the Ponemon Institute sponsored by anti-virus software developer Trend Micro Inc., 78 percent of the respondents said employee negligence or maliciousness led to data breaches in their business. The percentage was slightly higher, at 81 percent, for businesses with 100 employees or less.

These internal threats range from outright theft of business data to risky behavior on the network that could allow outside attackers to penetrate your network's defenses to losing laptops and removable devices with company data.

Devices that employees use in data theft incidents include thumb drives, external hard drives and Smart Phones and online file sharing services -- all devices and services that are easy to conceal.

No matter how much you trust your employees, you need to establish clear policies regarding the use of your network, including disciplinary actions that will be taken for violations of the policies.

In addition, you should implement a monitoring program to ensure employees are using the network appropriately. Inform your employees that their network usage, including the copying of data to devices outside the network, will be monitored.

Finally, ongoing employee education about basic network security and emerging data threats is a must for any business.

You can't prevent a data breach in your organization if an individual is determined to steal from you, but you can greatly reduce the risk by increasing the risk for employees to do so.

If you don't, you greatly increase the chance that you will add to the $250 billion a year that industrial espionage costs small

businesses in the U.S.