Stock market hackers have concocted a sophisticated phishing operation to tap into insider information related to the market.

More than 100 companies have been targeted by this group of cyber attackers–all but three are listed on the New York Stock Exchange or Nasdaq. The stock market hackers have not used the most advanced hacking techniques but it appears to be effective.

The cyber attacks are conducted through carefully constructed emails full of financial jargon to make them look legit. These emails were sent to a number of executives in the financial industry that gave up their usernames and passwords under false pretensions.

Hackers used these credentials to gain access to insider trading secrets. Cybersecurity company FireEye (FEYE) believes that these stock market hackers may have a background in investment banking.

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