MAS said on Tuesday it was advised about the dismissal by the US Court about the request through the courts for information.
On March 27, MAS said it had received a copy of the petition filed in the US court on behalf of one of the passengers.
It had then said its lawyers had been briefed and were on standby to deal with this although it has not yet been formally served.
The Malaysian Boeing 777-200ER, with 239 passengers and crew on board, vanished on March 8, about an hour after the Kuala Lumpur-Beijing flight took off from the KL International Airport at 12.41am.