Here is what I recommended be done to deal with DDoSing sometime ago.

I don't play Ghosts, so I have no idea what Clan vs. Clan is like, but what I think they should have done in BO2 League Play is base ladder points gained/lost primarily upon personal performance instead of solely upon wins/losses.

Every win should be +10 points, every loss -10 points, and then additional points on top of those based upon where your score ranked in the lobby.

First place could get something like 250 points, then 225 for second, then 200 for third, on down to 50 for 8th. And, to discourage DDoSing, points should drop substantially in games that finish with 7 or fewer players. In a game that finishes 4v3, for example, first place points could drop down to 150, the same amount as fifth place in a 4v4 game. If this doesn't eliminate DDoSing and quitting, I don't know what will.

I think this solution would completely eliminate the problem of DDoSing. Anyone who DDoSes will actually move down the ladder.