Vlad opened up a real can of worms with this war, there are a ton of western intelligence agencies working the region now and Ukraine has a lot of Vlad's many enemies from inside and outside his empire fighting there now. Ukrainian intelligence knows them all and must be like a traffic director or a dating service for allied intelligence agencies. Those who want to stir up shit inside Russian and Belarus or establish networks deep inside Russia. Many Ukrainians can operate freely inside Russia and speak perfect Russian, with supplied cash and paying bribes for anything they need they could do a lot of damage and perhaps are. A million ruble bribe would be hard for some sentry to pass up for turning a blind eye as a truck load of explosives' is driven out of an army base late at night. Warehouses are easy to rent and diesel fuel and fertilizer easy to acquire with cold hard cash. They could even put a tanker car of ANFO on a train to Crimea from deep in Russia, set off by GPS as it crosses the Kerch bridge, 50 tons of ANFO would take out both the rail and road bridges.