To learn that your company's confidential data was stolen -- not by any hacker, but by an employee -- is a nightmare scenario that no one wants to face.
But it's also a risk that's very real. The recent arrest of a former NSA contractor suspected of stealing classified government files is just the latest high-profile example, and security experts say all companies need to be on guard against potential insider threats.
It's not every day that thieving employees take to the digital black market to sell their company's sensitive information, but it does happen, and incidents have been occurring more frequently, said Andrei Barysevich, a director at security firm Flashpoint.
Flashpoint specializes in investigating marketplaces on the Dark Web for possible sales involving private company data. In one such case, it identified an employee of a major software company attempting to sell valuable source code for about $15,000.
Flashpoint has also detected other incidents of insiders trying to sell information from financial companies, healthcare providers and law firms, all of which hold valuable data such as bank account numbers, patient information and upcoming merger and acquisition deals.
In many of those cases, it appears the insider had access to sensitive data that no one at their companies bothered to monitor, Barysevich said. That's a serious problem, and he advises companies to segregate all valuable data away from employees who don't have a reason to use it. He also says they should create a culture where employees are aware of the insider threat.
Data protection company Bitglass has also been studying the insider threat. In a reportpublished last month, it found that one-third of organizations surveyed had experienced an insider attack within the past year in which data was leaked.
However, malicious insiders weren't the only ones to blame. Careless employees caused some of the leaks.
"Inadvertent leakage is also a big problem," said Salim Hafid, product manager for Bitglass.
Cloud-based applications and bring-your-own-device policies have only made it easier to accidentally share or publish confidential data, he said. As a result, more corporate data is getting out of company networks and into personal smartphones and file-sharing systems.