Are you sure, you want to discuss the "law of war", but didn't manage to at least visit the Wikipedia page of the term?
https://en.wikipedia.org/wiki/Law_of_war
Just focus on the box with the title "International humanitarian law". Quickly read through all the other treaties and finally land at Article 51 of Protocol I:
https://en.wikipedia.org/wiki/Protocol_I_to_the_Geneva_Conventions
To answer your questions:
No, the goal of #Ukraine is not to wrestle with the ethical questions about targeting key people at weapons manufacturers by stealing data from Tupolev.
What a weird question, by the way.
"Would that be legal under the laws of war?"
You should be able to answer that for yourself now with the links I gave you.
In case you can't find the full text linked at the bottom:
https://ihl-databases.icrc.org/assets/treaties/470-AP-I-EN.pdf
@eighthave That would most likely be considered state sponsored corporate espionage and is not really covered by conventions of war.
I sincerely doubt that Ukraine and the russia feel obligated to any peacetime treaties about international crime in relation to each other right now.