Microsoft CEO Steve Ballmer warned yesterday that recent security vulnerabilities represent a “new and growing challenge to innovation” and said that his company is under attack from “thieves, con artists, terrorists and hackers.” His remarks came at speech to the Churchill Club, a gathering in Santa Clara, California, of Silicon Valley businesspeople. Ballmer also mentioned Apple’s position in the marketplace. “Apple is doing some good, innovative work,” he said. In particular, Ballmer cited Apple’s Airport technology. “It’s easy to forget how truly groundbreaking this technology was.” However, he also noted that Apple doesn’t appear to be stealing much of the computer market from Windows-based rivals. “I don’t see their basic position in the market changing.”