The snooping technology has been available for three years, but very few people knew it could be used until recently, says David Martin, professor of computer science at the University of Denver, which is associated with the Privacy Foundation.
Richard Smith, chief technology officer at the Privacy Foundation, wrote in a column attached to the advisory that the new snooping technology "made me fall out of my chair" and called it "very illegal and also very easy to do."
But one industry analyst says he wasn't sure the concern is that worrisome. "This email wiretapping doesn't strike me as a super-high priority for corporate users, but it could be if you are involved in sending emails that are potentially compromising," says Dana Gardner, an analyst at Aberdeen Group in Boston.
The foundation details a longer, 15-step method in its advisory.