According to a news report Department of Homeland Security review which said "performance, organizational and technical" failures had allowed Iraq war veteran Omar Gonzalez to evade security and make his way into the building in September.
The review said 42-year-old Gonzalez, who was carrying a knife during the incident, could have been stopped by a Secret Service officer who was supposed to be stationed on the North Lawn with an attack dog.
However, at the time Gonzalez scaled the fence and bolted across the lawn, the officer in question was sitting in his van making a personal call on his cellphone.
Because of this lapse, the attack dog was unable to "lock onto" Gonzalez and "may not have seen" him at all, the review said.
The intrusion was the most serious incident in a string of security lapses involving President Barack Obama, which ultimately led to the resignation of Secret Service director Julia Pierson in October.
Obama and his family had left the White House shortly before the intrusion took place.
The review found authorities had also failed to properly investigate Gonzalez after he had come to the attention of law enforcement months earlier, The Times reported.
Gonzalez was arrested on gun charges in Virginia in July before being stopped again outside the White House a month later while carrying a hatchet. He was not arrested on that occasion.
The review revealed that Gonzalez was spotted by officers patrolling the street outside the White House climbing over a section of fencing missing an ornamental spike.
They ordered him to stop and drew their firearms but elected not to shoot because they did not believe he was armed.
Another officer stationed near the outer front door of the White House also decided not to use lethal force when confronted by Gonzalez because he did not believe he was armed.
The officer did not follow Gonzalez into the building because he believed the door was locked and that the intruder was cornered, the review said. But the door was open, allowing Gonzalez to overpower a female officer stationed there.
Gonzalez entered the East Room of the White House before exiting and charging down a hallway. He was eventually apprehended by two agents who had just finished their shifts.