Contrary to popular belief, most cyber attacks or data breaches don't come from outside a company. The majority are the result of mistake, for example, when an employee loses a laptop computer containing customer data. But a number of attacks are by former employees who may still have access to the company's sensitive data or systems. In one such case, an IT engineer has been convicted on criminal charges of hacking the internal computer network of Locke Lord after he stopped working for the global law firm four years ago.

A federal jury in Dallas found the former employee, Anastasio N. Laoutaris, guilty of two counts of knowingly accessing a computer network without authorization and intentionally issuing commands and codes that caused damage to the network.

According to the federal prosecutor, Laoutaris, who was an IT engineer for Locke Lord LLP from 2006 to August 2011, accessed the firm's computer network without authorization on Dec. 1, 2011, and Dec. 5, 2011, and on both occasions, issued instructions and commands that caused significant damage to the network, including deleting or disabling hundreds of user accounts, desktop and laptop accounts, and user e-mail accounts.