is there any way to change properties of vanilla blocks?

Not directly, but there are workarounds. A simple one would be to replace the block with a modded copy of the block whenever anything interacts with it. (If you wanted to increase the hardness of stone, for example, you could create a modded block that uses the vanilla stone texture, and replace normal stone with modded stone whenever the player clicks on it.) 

For that you'd just need to change the loot tables. You can make one of your loot tables override a vanilla loot table by giving them the same registry name.