Looks like they don't even know about it yet, as the "Hacked The UnderTaker" message left by the breachers on sonymusic.com.br, is still intact.
The Sony network and its services got hacked more than a dozen times over a period of 2 months. Quite alarming it is for everyone, but the company is yet to learn from its mistakes. Check Here
It's pretty apparent to everyone that Sony hasn't plugged holes yet, and has failed to be alert.