Lieberman, the chairman of the Homeland Security and Government Affairs Committee, said he believes the attacks were in retaliation for economic sanctions that the United States and Europe have put on Iranian banks.
He declined to provide evidence for why he believes that Iran and the Quds force, a special unit of its Revolutionary Guard, were behind the attacks.
"This is a theory, but I think it has a basis," Lieberman said, adding his opinion is based on discussions with unnamed individuals.
"It reminds us of our vulnerability, which is part of why they are doing it," Lieberman said. "And it's a warning to us that if we take action against their nuclear weapons development program that they have the capacity to strike back at us."
Lieberman said Islamic extremist websites claimed credit for the attacks, and the extremists said they were a response to a controversial anti-Muslim YouTube video. But the senator expressed skepticism about the credibility of those claims.
Lieberman is the lead author of legislation that would pressure operators of critical infrastructure, such as banks, gas pipelines or water treatment plants, to meet minimum cybersecurity standards. But Republicans blocked his bill last month over concerns that it would burden businesses with ineffective regulations.
The White House is working on an executive order that would accomplish many of the goals of Lieberman's Cybersecurity Act.
The United States launched its own cyber attacks on Iranian nuclear facilities, according to a New York Times report. The article stated that the Obama administration used the Stuxnet computer virus to destroy Iranian centrifuges.