The three-time champions got their preparations for the tournament underway on Tuesday by flying out to Italy for an 11-day training camp.
"I don't want to finish in the semi-finals or go to Brazil to soak up the sun. I have a clear goal - the greatest possible success, the World Cup trophy," Lahm is quoted as saying by Goal.com.
"We have to work especially on our defence and have conceded too many goals and allowed too many good chances. We must pay more attention to how the defence dropped. The whole team needs to."
Germany finished in third place at the 2010 World Cup in South Africa.