Sourcefire has chosen a Citrix Systems sales executive to be the company's new CEO.

John Burris, who is currently head of worldwide sales and services at Citrix, will replace Sourcefire's current CEO, Wayne Jackson, effective from July 14. Jackson, who had led the company from 2002 though its initial public offering last year, had announced that he would step down in late February.

"We are privileged to have attracted a leader of John's calibre and experience to guide the company going forward," said Jackson in a webcast recording, released on Monday. He did not say why he was stepping down as CEO.

Burris, 53, had previously served on Sourcefire's board of directors. He will continue to have a seat with the board when he becomes CEO, Sourcefire said.

Sourcefire has lost money since going public last year, and its stock has dropped about 50 percent since then. The company is best known as the creator of the Snort intrusion-detection software.

In August 2007 it acquired the open-source ClamAV antivirus software and is now working to integrate that code into its product line.