"I did not take any designs away from Ferrari. Someone passed on the designs but it wasn't me," Stepney told Italy's La Repubblica.
With 'team orders' now legal in Formula One, Ferrari's Felipe Massa will have to raise his game right from the start of the season in Australia next week.
Michael Schumacher won a point despite retiring as BMW Sauber's Robert Kubica was disqualified from the race.
Kimi Raikkonen believes he still has the speed that Ferrari need despite reports that the Formula One team are lining up a replacement for 2016 in fellow-Finn Valtteri Bottas.
The Dutchman's run of nine successive wins was snapped as he broke down on lap four with a brake problem.
In the interests of better visibility, teams were told last month they could fix mirrors to the halo head protection device that encircles the cockpit and that became mandatory this season.
Vettel, 17 points behind Hamilton after a commanding win in Belgium last Sunday, has previously triumphed at Monza with Toro Rosso and Red Bull and will fancy his chances of the hat-trick at the super-fast track outside Milan.
Max Verstappen won the first sprint race of the Formula One season at the Chinese Grand Prix on Saturday.
'The team is developing and closer together year by year so I hope that this year we get to have a lot of fun -- fun means win a lot of races and then ultimately you are fighting for the championship'
Ferrari have bucked the global economic crisis squeezing Formula One by agreeing a sponsorship deal with carmaker Tata.
Former Ferrari technical director Ross Brawn has made clear that he favours a return to the Italian team over Formula One rivals when he completes a sabbatical at the end of the year.
Brazilian Felipe Massa is likely to stay with Ferrari next year alongside Fernando Alonso, team principal Stefano Domenicali said on Thursday.
Sebastian Vettel handed Ferrari their first Canadian Grand Prix pole position since Michael Schumacher in 2001 on Saturday while Formula One championship leader Lewis Hamilton qualified fourth for Mercedes. Vettel, 14 points behind the Briton, will start from the front for the fourth time at the Circuit Gilles Villeneuve after setting a track record of one minute 10.764 seconds on a sunny afternoon.
Stefano Domenicali resigned as Ferrari's Formula One team principal on Monday, and the company's North America president and chief executive Marco Mattiacci was appointed as his replacement.
Italian doctor Michele Ferrari denied on Tuesday accusations from the US Anti-Doping Agency (USADA) that he masterminded a doping programme for American cyclist Lance Armstrong.
Ferrari agreed on Friday to end legal action against McLaren over last year's spy scandal for the good of Formula One.
Ferrari launched four other models -- 488GTB, 458 Spider, 458 Speciale and F12 Berlinetta.
Ferrari boss Jean Todt dropped a hint on Sunday that he expects Kimi Raikkonen to be heading for his Formula One team next season.
"It was not a problem of the mechanics, it was our problem and we have to make sure we fix it"
Summary of sports events and persons who made news on Sunday
Sebastian Vettel drove a flawless tactical race to claim his maiden victory for Ferrari at the Malaysian Grand Prix on Sunday, registering the first Formula One win for the Italian team since 2013.
Verstappen took pole position for the Saudi Arabian Formula One Grand Prix on Friday with Ferrari's Charles Leclerc qualifying alongside on the front row.
The film has been getting some mixed reviews.
While Ferrari's Fernando Alonso rates 2012 as his best season in Formula One, the Spanish driver says his car must be quicker next year if he is to fight for the title again.
Ferrari promised to pull out all stops on Sunday to help Fernando Alonso claim the Formula One drivers title and with the help of a rulebook loophole they head to the season finale still in the fight.
Kimi Raikkonen is not assured of racing for Ferrari in Formula One next season, team president Luca di Montezemolo said on Wednesday. Rumours have swirled for months that Raikkonen will be replaced by Renault's Fernando Alonso for next year despite the Finn's contract with Ferrari running until the end of 2010.
Mark Webber ended speculation about a move to Ferrari by signing an extension to his Red Bull contract that keeps him alongside Formula One world champion Sebastian Vettel for a fifth season.
Ratan Tata pored over every inch of the new million-euro LaFerrari on the Italian supercar maker's stand at the Geneva auto show.
Spaniard Fernando Alonso handed Ferrari their first Formula One pole since 2010 in a wet British Grand Prix qualifying session on Saturday.
The Brazilian has struggled for form in recent years but has agreed a one-year extension amid continued speculation that world champion Sebastian Vettel could join Alonso at Ferrari from 2014.
Charles Leclerc seized pole position for the Belgian Formula One Grand Prix on Saturday ahead of team mate Sebastian Vettel who completed a front row lockout for Ferrari.
Former champions Renault followed Ferrari's lead on Wednesday and threatened to quit Formula One at the end of the season unless the governing body rewrites the 2010 rules. Champions Ferrari, Formula One's glamour team who have competed in every championship since 1950, issued a similar threat on Tuesday in response to the introduction of an optional 40 million pounds budget cap.
The F1 world champion said he could not imagine driving for any other team than Ferrari and he would welcome the Finn as a team mate.
Ross Brawn said the memory of Nigel Mansell's failure to win the 1986 title from a similar position still lingers.
Ferrari unveiled their new Formula One car, the SF70-H, with the minimum of fanfare after a disappointing 2016 season but plenty of hope among fans that the Italian team will return to winning ways.
Formula One champions Ferrari have lightened Kimi Raikkonen's load by giving the Finn a new slimmed-down car for Sunday's Spanish Grand Prix. Ferrari said the 2007 champion, whose last win was at the Circuit de Catalunya a year ago, would get a lighter chassis than Brazilian team mate Felipe Massa for the start of the European season.
World Champions Red Bull and rivals Ferrari will withdraw from the Formula One Teams Association (FOTA) after failure to reach agreement over cost cutting measures.
