There really is nothing new. I remember, many years ago, the Christmas EXEC that flooded the IBM mainframe network in a matter of hours and caused great problems.
Some wag at the time suggested a "hunter/catcher" routine that would have doubled the problem.
Regardless of the legality, the problem is that these would not just hurt the target but anyone that shares any of the resources along the way. You might not be able to bring the net to its heels by yourself but get a few people doing this and ....
The only way is to not let them know they have got to you.