The more important problem is that we don’t even know if this attack:
1) ever occurred
2) if it did occur, was it even the US
3) if it was even an attack, was it in fact a cyberattack at all (you would want to protect actual human assets who do physical damage in say industrial control systems as an insider job by saying it was a remote attack using some sort of zero day attack)
Anonymous government sources, especially in cyber security, have a track record of persistent lying
Remember the China chip hacking story by Bloomberg built on anonymous government sources. The alleged fake news was never retracted - even though it was technically not a possible attack if you know how chips are made. (There are chips that had arguably deliberately installed flaws - the Intel chip with the OTP generator that was trivially crackable and the RSA keyfob with the default NSA backdoor).
The China chip hacking story was an invented story by Bloomberg. Everyone else denied it including Apple as the customer, US government, the supplier of the chip etc. Bloomberg fabricated the story. Ever since, I do not trust Bloomberg as a reliable source of information.
"Nitro Zeus was part of an effort to assure President Obama that he had alternatives, short of a full-scale war, if Iran lashed out at the United States or its allies in the region."
Tens of millions of dollars, thousands of people... That's not secrecy, just plausible deniability.
Anonymous government sources, especially in cyber security, have a track record of persistent lying
Remember the China chip hacking story by Bloomberg built on anonymous government sources. The alleged fake news was never retracted - even though it was technically not a possible attack if you know how chips are made. (There are chips that had arguably deliberately installed flaws - the Intel chip with the OTP generator that was trivially crackable and the RSA keyfob with the default NSA backdoor).
https://www.bloomberg.com/news/features/2018-10-04/the-big-h...
https://siliconangle.com/2018/10/22/apple-amazon-super-micro...
https://www.wired.com/2013/09/rsa-advisory-nsa-algorithm/