Mr. Obama decided to accelerate the attacks — begun in the Bush administration and code-named Olympic Games — even after an element of the program accidentally became public in the summer of 2010 because of a programming error that allowed it to escape Iran’s Natanz plant and sent it around the world on the Internet…

…If Olympic Games failed, he told aides, there would be no time for sanctions and diplomacy with Iran to work. Israel could carry out a conventional military attack, prompting a conflict that could spread throughout the region…

…A similar process is now under way to figure out the origins of another cyberweapon called Flame that was recently discovered to have attacked the computers of Iranian officials, sweeping up information from those machines. But the computer code appears to be at least five years old, and American officials say that it was not part of Olympic Games. They have declined to say whether the United States was responsible for the Flame attack….

…But by the time Mr. Bush left office, no wholesale destruction had been accomplished. Meeting with Mr. Obama in the White House days before his inauguration, Mr. Bush urged him to preserve two classified programs, Olympic Games and the drone program in Pakistan. Mr. Obama took Mr. Bush’s advice.