A group of hackers are targeting publicly traded companies to obtain insider trading tips and win on the US stock market, according to research by US network security company FireEye.
The report, which calls the group FIN4, says that hackers broke into the email accounts of top executives and legal advisors to steal secret information that could one day move a company's share price.
This included regulatory filings, documents on merger activity and legal cases.
The English-speaking group, who are probably from the US or Europe, have collected information from nearly 100 publicly traded companies or advisory firms.
Most of them have been from pharmaceutical or healthcare companies, whose shares are particularly sensitive to mergers and acquisitions speculation.
Instead of using traditional malware, the group sends weaponised versions of "legitimate corporate files" such as emails. By not using malware they have been able to evade traditional detection and attribution.
Dan McWhorter, VP of threat intelligence at FireEye said:
Advanced threat actors conducting attacks to play the stock market to their advantage has long been a worry but never truly seen in action.
FIN4 is the first time we are seeing a group of very sophisticated attackers actually systematically acquire information that only has true value to a criminal when used in relation to the stock market.