Triple world champion Lauda, now the Mercedes team's chairman, revealed he is aware of the precise term of the reigning world champion's current deal.
"I know Sebastian's contract with Red Bull and it's long term," the famous Austrian told Italian television Griglia di Partenza.
"That's why we didn't try to take him under contract at Mercedes," added Lauda.
At the same time, Red Bull team owner Dietrich Mateschitz told Italy's La Gazzetta dello Sport daily that Vettel is committed until the end of 2014.
"Anything else was never in question," said the billionaire.
But what about 2015 and beyond? Would Red Bull consider signing Fernando Alonso, should German Vettel be wooed to Ferrari, who have ruled out putting the two together?
"If he (Alonso) is still racing, then why not?" Mateschitz said.
The publicity-shy Mateschitz also steered away from right-hand man Marko's recent criticism of Mark Webber, saying one of Red Bull's strengths has been its "perfect drivers".
"Webber is both a strong and charismatic character and an exceptional driver," he insisted.
Mateschitz, however, acknowledged that many in Formula One would like to see Red Bull finally beaten in 2013.
"It's an understandable desire, but it's also understandable that we are going to try to prevent it," he said.
Mateschitz said "sports" like Formula One will "always be an important part" of the energy drink Red Bull's budget, and is not ruling out entering the world of two wheels.
"MotoGP is a fantastic sport that has always fascinating me," he said, admitting a foray for Red Bull is "certainly conceivable".