The fastener circled in red has various names.

Some call it 12-point, some call it triple-square(3x4=12).

Lisle Tools(http://www.lislecorp.com) makes at set that Pep Boys carries. Lisle Tool part number 60750. I forget the price - something like $10-$12 dollars. I learned the hard way when I didn't have one to remove a 12-point bolt near the differential.