The media has been reporting that it may have ran out of fuel and crashed in the Indian Ocean, but that seems unlikely given the original flight path. Plus they add an extra hour of fuel or enough to reach two other airports, whichever is greater.
The plane could have made it to India, Pakistan, Afghanistan, Iran and Oman (which neighbors the terrorist hotbed of Yemen). Maybe the far southern tip of Saudi Arabia also (US intelligence leaks say the Saudi government funded 9/11). The possibility that they refueled somewhere and continued on can't be ruled out either. Another possibility is rogue employees filled the tank up in Malaysia.
Where they are at depends on what the end motive is.