It's likely not a virus. It could be a multitude of different things.
It could be your router, firewall, ethernet drivers ect. Overwhelming your router seems unlikely, I've never seen that before. It could be overheating though I guess.
Also if you're connected to the net wirelessly that can cause a whole bunch of connection issues.
The most likely culprit though is the War Thunder downloader/launcher. If you can patch a different way, do that.
