It's scary enough when someone's personal email is hacked or companies endure a limited data breach, but imagine what it would be like for hackers to have access to an entire company's worth information … for a decade. That nightmare is essentially what happened at Nortel Networks Ltd., and the bad dream still hasn't ended.

The Wall Street Journal today published an in-depth examination of the unfortunate tale of woe that's still unfolding at the once-major Canadian telecommunications company, which is currently in the final throes of divesting pieces of itself as the result of a 2009 bankruptcy filing.

According to the WSJ story, a group of Chinese hackers breached Nortel's computers dating back as far as 2000, and had access to its entire corporate network for nearly a decade. After stealing seven executives' passwords, including the CEO's, the hackers were able to download technical documents, research-and-development reports, business plans, employee emails and other documents, Brian Shields, the 19-year Nortel employee who led the internal investigation team, told the WSJ.

Shields added that the hackers hid espionage software so deeply within employees' computers that it took his team years to recognize the full extent of the infiltration.

They “had access to everything,” Shields told the WSJ. “They had plenty of time. All they had to do was figure out what they wanted.”

A Nortel internal report noted that once the company discovered the breach, it “did nothing from a security standpoint” to repel the hackers other than resetting the seven passwords. The WSJ also reports that as part of its internal investigation, Nortel made no effort to determine if its products also were compromised by the hackers.

Shields told the WSJ that Nortel didn't resolve the hacking problem before peddling its assets, and didn't disclose the hacking to prospective purchasers, leaving the door open for Nortel asset buyers to possibly have inherited spyware that infected Nortel systems.

For more on the story, read the full WSJ report.