Symantec Corp., the biggest maker of computer-security software, fired President and Chief Executive Officer Steve Bennett and named board member Michael Brown to lead while the company seeks a replacement.

Bennett took over as CEO in July 2012. A special committee of the board will begin looking for a permanent CEO with an executive search firm, the Mountain View, California-based company said Thursday in a statement.

Bennett leaves a company whose stock has fallen 15 percent in the past year amid declining revenue. Symantec remains committed to its target of revenue growth of more than 5 percent by fiscal 2017, Chairman Daniel Schulman said in the statement.

“Our priority is now to identify a leader who can leverage our company’s assets and leadership team to drive the next stage of Symantec’s product innovation and growth,” Schulman said. “This considered decision was the result of an ongoing deliberative process, and not precipitated by any event or impropriety.”

The shares rose 1.6 percent to $20.91 at the close of trading in New York before the announcement. But in aftermarket trading, the stock was down 6.5 percent at $19.54.