Georgetown University in Washington has called in the U.S. Secret Service to investigate a server breach that may have exposed confidential information including the names, dates of birth and Social Security numbers belonging to more than 41,000 people. The breach appears to have been caused by an external hacker and involved a server that was being managed by a Georgetown University researcher as part of a grant to manage information on the various services provided through the District of Columbia's Office of Aging, according to a university statement released Friday.