Mr Obama and his family were not at the White House when the intrusion happened, having departed about 10 minutes earlier by helicopter.
The incident is the latest in a string of security lapses overseen by the Secret Service, tasked with guarding the Obama family.
On 16 September, Mr Obama is said to have been in an Atlanta lift with an armed security contractor who had assault convictions.
This contravened a protocol that only members of the Secret Service are allowed to carry weapons in the presence of the president.