Research shows that the majority of malicious insider attacks are caused by disgruntled employees and employees planning to leave the company. Even if there isn’t an employee with a grudge, users fall prey to phishing attacks and click on malicious links on social networking sites that lead to breaches. Write policies that people can understand and follow. Train employees in safe computing habits. And be vigilant in monitoring user activity. The key is understanding the attacks, the possible motivations and the primary areas where controls can be most effective.”]
Source: https://www.darkreading.com/analytics/how-to-prevent-data-leaks-from-happening-to-your-organization