In his new book, "The Great War of Our Time: The CIA's Fight Against Terrorism From Al Qaeda to ISIS," former CIA Deputy Director Michael Morell apologizes to former Secretary of State Colin Powell for flawed CIA intelligence that Powell outlined in a 2003 speech at the United Nations.

"I thought it important to do so because here's a man with an incredible reputation, well-deserved over a long period of time, and he went out there and made this case, and we were wrong," CBS News senior security contributor said Monday on "CBS This Morning."

On February 5, 2003, Powell told the U.N. Security Council Iraq had "biological weapons and the capability to rapidly produce more, many more," and had shipped "chemical weapons from production facilities out to the field."

In the book, Morell details how the CIA was wrong to conclude Saddam Hussein had weapons of mass destruction.

"We said he has chemical weapons, he has a biological weapons production capability, and he's restarting his nuclear weapons program. We were wrong on all three of those," he said.

Almost a year after he made the United States' case for war to the world, Powell said he was not sure he would have supported the invasion of Iraq if he knew Iraq had no weapons stockpiles.

Morell said he was not a senior official at the time, so it wasn't up to him to apologize. But after learning the intelligence community had still not reached out about to Powell about the flawed evidence, Morell decided it was time.

"This has been on him, in a sense, for a very long period of time, so I wanted to apologize," he said.

Morell also expresses concerns over the possibility the Islamic State of Iraq and Syria (ISIS) could launch a 9/11-scale attack against the U.S.

"One of the key lessons in the fight against terrorists is that you have to keep the pressure on them. If you keep the pressure on them, you make it very difficult for them to plot, you make it very difficult for them to plan, you make it very difficult for them to attack, because they're worried about their own security," he said. "As soon as you take that pressure off, they start rebuilding. We've seen that over and over and over again."

As the U.S. tries to keep pressure on the terrorist group, officials are becoming increasingly worried by the pace at which their brand is spreading.

ISIS's presence on social media has already played a part in influencing two gunmen to attempt to carry out an attack on a Texas art contest featuring cartoon images of the Prophet Muhammad, teens traveling to Syria and Iraq to join terrorist groups and inspiring lone wolves around the world.

"It's Madison Avenue-quality social media that's radicalizing these guys," Morell said. "It's very difficult to shut it down because of the nature of the internet. If you shut it down over here, it pops right back up over here."

Morell said ISIS' threat is "growing every day."

Morell also commented on a recently published report by famed journalist Seymour Hersh accusing the Obama administration of lying about the Osama bin Laden raid, saying the report is "all wrong."

"I started reading the article last night, I got a third of the way through and I stopped, because every sentence I was reading was wrong. The source that Hersh talked to has no idea what he's talking about," Morell said.

Award-winning investigative journalist Seymour Hersh released a brazen report Saturday claiming the White House's account "might have been written by Lewis Carroll." Among his claims, he says bin Laden was already being held captive by the Pakistan's ISI intelligence agency in the Abbottabad compound and that Pakistan's top senior officials knew of the raid and helped SEAL helicopters clear Pakistani airspace.

He also said the CIA learned of bin Laden's whereabouts from a former Pakistani official who was offered $25 million from the U.S.

Morell said that is "not true."

"The person was obviously not close to what happened. The Pakistanis did not know," he said. "I talk about in the book how we actually made a decision, the president made a decision not to tell the Pakistanis. The Pakistanis were furious with us. The president sent me to Pakistan after the raid to try to start smoothing things over. The Pakistanis did not know. This article is wrong."