Northrop Grumman said on Thursday its Chief Executive Officer Wes Bush would step down, effective Jan. 1, 2019.

The company said its board has elected Chief Operating Officer Kathy Warden to take over Bush's role early next year.

Warden joined the company in 2008 and served in several roles, including vice president and general manager of its cybersecurity business, president of its former Information Systems sector, and president of its Mission Systems sector.

Northrop said Warden will join the board of directors, effective immediately.