Cybersecurity firm FireEye Inc said on Thursday that Chief Executive David DeWalt would step down from that role on June 15 and be succeeded by President Kevin Mandia.
Shares of the company, which lowered its full-year revenue forecast, fell 7.7 percent to $14.75 in after-hours trading on Thursday.
Kevin Mandia currently leads the company's Mandiant forensics unit, which has probed some of the biggest cyber attacks to date, including the 2013 holiday attack on Target Corp and the attack on Sony Pictures Entertainment .
Mandiant was founded in 2004 by Mandia, a former U.S. Air Force cyber-forensics investigator who also co-authored an influential textbook on the subject.
DeWalt, who is also FireEye's chairman, will stay on as executive chairman, the company said.
The company forecast full-year total revenue in the range of $780 million-$810 million, lower than its previous range of $815 million-$845 million.
Analysts on average had expected revenue of $828.6 million.
FireEye, which provides Web, email and malware security to businesses and governments, said its revenue jumped 34 percent to $168 million in the first quarter ended March 31, from $125.4 million a year earlier.
However, the net loss attributable to shareholders widened to $155.9 million, or 98 cents per share, from $134 million, or 88 cents per share.
Excluding items, the company lost 47 cents per share.
Analysts on average had expected revenue of $171.8 million and a loss of 50 cents, according to Thomson Reuters I/B/E/S. (Reporting by Narottam Medhora in Bengaluru; Editing by Ted Kerr and Sriraj Kalluvila)