The random chatter of several hundred Microsoft engineers filled the cavernous executive briefing center recently at the company's sprawling campus outside Seattle.
Within minutes after their meeting was convened, however, the hall became hushed. Hackers had successfully lured a Windows laptop onto a malicious wireless network.
"It was just silent," said Stephen Toulouse, a program manager in Microsoft's security unit. "You couldn't hear anybody breathe."
The demo was part of an extraordinary two days in which outsiders were invited into the heart of the Windows empire for the express purpose of exploiting flaws in Microsoft computing systems. The event, which Microsoft has not publicized, was dubbed "Blue Hat"--a reference to the widely known "Black Hat" security conference, tweaked to reflect Microsoft's corporate color.