Here's another good example of Ukrainians being pragmatic: https://kyivinsider.com/russias-largest-cities-rocked-by-wave-of-coordinated-arson-and-explosions/

Nothing has been admitted officially AFAIK. But it looks like Ukrainian intelligence is defrauding, coercing, blackmailing, and straight up paying Russians on a large scale into committing acts of arson and sabotage, mostly against "civilian" targets.

Is that "clean" and "ethical"? Meh. It's effective. If you can defraud or coerce a desperately poor Russian pensioner into setting a business on fire and causing $100k of damage, that probably translates into something like $20k less tax revenue for the Russian government from the business, and wasting another $20k of government money on a trial and imprisonment. $40k less going to war is probably in the ballpark of what it would take to prevent one Ukrainian casualty.