Wouldn't suprise me if they are cheating.
He is on the throttle real early in every corner.
The rear never steps out, not even when going over bumbs so that means the car got super rear end grip.
They got something special that Vettel takes full advantage off but Webber cant for some reason.
Might not be cheating, until the rest of the teams finds out about it and looks into it.
The FIA is known for letting illegal cars pass.
It's only after the competition noticeses that X team is cheating that the Fia wakes up, but instead of DQ team X from the entire season they just gives them a slap on the wrist.
Barichello said during the Ferrari years that one reason why Schumi was so much faster then him was because schumi nailed the throttle to the floor and trusted TC to take care of it, Barichello never had that trust in the TC and lost out because of that to Schumi.
Could be that Vettel trusts their (cheating) system and takes full advantage out of it but webber doesn't.