The consensus is that Iran attacked the US in a semi-sophisticated cyber-terrorist attack. (The target is not military, but civilian infrastructure, so any way you look at it, this is terrorism.)
This was apparently already common knowledge in some circles in October:
Iranian hackers renewed a campaign of cyberattacks against U.S. banks this week, targeting Capital One Financial Corp. COF +0.36% and BB&T Corp. BBT +0.07% and openly defying U.S. warnings to halt, U.S. officials and others involved in the investigation into the attacks said.
The attacks, which disrupted the banks' websites, showed the ability of the Iranian group to sustain its cyberassault on the nation's largest banks for a fifth week, even as it announced its plans to attack in advance.
U.S. officials said the attacks against banks, and others against Middle Eastern energy companies, were sponsored by the Iranian government and approved at high levels as part of a low-grade cyberwar that officials warned could lead to retaliation.
Unclear is at what point attacks on individual banks constitute an assault on the overall financial system that would call for a forceful response from the U.S. military, which has formed a "Cyber Command" to help defend government computers and critical civilian networks.
"It is a fair question," said a senior U.S. official. "I am not sure I have the answer to it."