Technical trade secrets were stolen from the steel production and manufacturing plant design divisions of ThyssenKrupp AG in cyber attacks earlier this year, the German company said on Thursday. "ThyssenKrupp has become the target of a massive cyber attack," the industrial conglomerate said in a statement. In breaches discovered by the company's internal security team in April and traced back to February, hackers stole project data from ThyssenKrupp's plant engineering division and from other areas yet to be determined, the company said.