User Ignorance : Employees who have access to company data may not have had security training; yet when employees are trained in basic IT security practices, serious security breaches decline.
Poor Password Management: Another familiar tune, password policies so strict that users write their passwords on a Post-It and post it on the back of their monitor (or, in tighter security environments, on the bottom of their keyboard) where it's easily found; or policies so lame that passwords are easily cracked or even guessed. Password policy is balancing act,and many if not most companies are off-balance.
Rampant Account sharing: Data access accounts and log-ins get shared, sometimes widely and sometimes wildly, with everyone in the company, it seems, knowing how to access the sensitive stuff.
Unrestricted Access:: The only people who require access to sensitive data are the ones who work with the sensitive data. And that tends to be a far smaller number of people than the number who can access the confidential files.
Excessive Data Portability: The amount of storage employees carry for personal, much less business purposes, has become staggering. High capacity thumb drives, iPods, phones, you name it and it has the potential to become a vehicle for transporting sensitive data out of the supposedly protected environment. Yet database activity monitoring and access controls and other security tools remain sparsely implemented.
Each of these vulnerabilities offers opportunity for both malicious exploitation of your data and bonehead mistakes and sloppiness that result in a breach.
And each can be remedied with education, effort, and effective policies, effectively enforced.
The complete Dark Reading Report Protecting Your Database From Careless End-Users can be downloaded here (registration required).