Stuxnet went far beyond shutting down or disrupting operations. After infecting Seimens-made control systems, it sent out instructions that would damage delicate centrifuges, in which bomb- or reactor-grade uranium is separated from naturally occurring uranium. In a Hollywood touch, the worm also displayed normal information on computer screens so that human operators wouldn’t notice the attacks.
Stuxnet is widely regarded as the most sophisticated piece of malicious software ever created. Earlier this year, the New York Times reported that Stuxnet was tested by Israeli agents on centrifuges at an Israeli site, and pointed to this and other clues that Stuxnet may have been “designed as an American-Israeli project to sabotage the Iranian program.”
But much is not known. “We don’t know what it’s for. The initial speculation is that it was a precursor to the next Stuxnet, but we don’t know anything,” says Bruce Schneier, a cryptologist and security expert. “It is what it is. We don’t know.”
Duqu creates a kind of “back door” that can receive commands from, and deliver information to, a so-called command-and-control server somewhere in India. (That server is not known to have sent out instructions, Symantec says.) The company says the back door stays open for only 36 days, and then the malware deletes itself.
Symantec says its researchers—after sending out a detection tool following the discovery of the code in Europe—have found Duqu on industrial computers “around the globe.” Like Stuxnet, which infected thousands of computers in 155 countries last year, Duqu got aboard victim computers by means of a stolen digital certificate—a cryptographic code that authenticates a piece of software on a target machine. “On the whole, this underscores the critical importance of cyberspace security policy and practices, national, regionally, and internationally,” Deibert says.