Hackers working from China have reportedly had access to Nortel’s networks since breaching the telecommunication company’s networks as far back as 2000. According to a report from the Wall Street Journal, hackers stole seven passwords from Nortel’s top executives, granting them access to reports, business plans, employee e-mails and other documents.

Brian Shields, a former Nortel employee, led the internal investigation into the breach and told the Journal that the hackers “had access to everything.” An internal report indicated that Nortel reset the passwords that had been taken but didn’t do anything else to keep the hackers out.

Nortel, which filed for bankruptcy in 2009, did not immediately respond to a request for comment on the story.

The report said that Nortel discovered the hackers in 2004, after an employee noticed some unusual downloads being made in the name of an executive. Shields told the paper that he found that the hackers have been using China-based Internet addresses for the transmissions. He said that he noticed unusual transmissions every month or so, but that Nortel decided to ignore his recommendations to enhance network security.

The report said that former Nortel CEO Mike Zafirovski said that the company did not believe the hacking was a “real issue” and that Nortel did not feel compelled to pass its knowledge of the hacks to potential buyers.

Companies such as Ciena, Ericsson and Avaya have purchased parts of Nortel’s business. Zaifrovski told the newspaper that he does not think the threats could have been passed on to those companies. Ericsson and Avaya told the paper that they are not concerned about the issue, while Ciena said that it was not made aware of “any prior infiltration” of Nortel’s network.

What isn’t clear from the article is how the hackers obtained the passwords in the first place.

Hackers interested in corporate espionage often target individuals by using phishing scams that trick users into giving up their personal log-in information.

In June’s high-profile hack of the Gmail accounts of some senior U.S. officials, The Washington Post reported that hackers — also believed to have been based in China — used phishing scams that tricked officials into giving up the information or clicking on links that infected their computers with a virus.

The Journal’s report comes as China’s Vice President Xi Jinping makes a high-profile, but highly guarded trip to the United States, The Washington Post’s William Wan reported.

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