Controllers, and the electrical regulators they run,
became a focus of sanctions efforts. The trove of
State Department cables made public by
WikiLeaks describes urgent efforts in April 2009
to stop a shipment of Siemens controllers,
contained in 111 boxes at the port of Dubai, in the
United Arab Emirates. They were headed for Iran,
one cable said, and were meant to control
“ uranium enrichment cascades” — the term for
groups of spinning centrifuges.
Subsequent cables showed that the United Arab
Emirates blocked the transfer of the Siemens
computers across the Strait of Hormuz to Bandar
Abbas, a major Iranian port.
Only months later, in June, Stuxnet began to pop
up around the globe. The Symantec Corporation,
a maker of computer security software and
services based in Silicon Valley, snared it in a
global malware collection system. The worm hit
primarily inside Iran, Symantec reported, but also
in time appeared in India, Indonesia and other
countries.
But unlike most malware, it seemed to be doing
little harm. It did not slow computer networks or
wreak general havoc.
That deepened the mystery.
A ‘Dual Warhead’
No one was more intrigued than Mr. Langner, a
former psychologist who runs a small computer
security company in a suburb of Hamburg. Eager
to design protective software for his clients, he
had his five employees focus on picking apart the
code and running it on the series of Siemens
controllers neatly stacked in racks, their lights
blinking.
He quickly discovered that the worm only kicked
into gear when it detected the presence of a
specific configuration of controllers, running a set
of processes that appear to exist only in a
centrifuge plant. “The attackers took great care to
make sure that only their designated targets were
hit, ” he said. “It was a marksman’s job.”
For example, one small section of the code
appears designed to send commands to 984
machines linked together.
Curiously, when international inspectors visited
Natanz in late 2009, they found that the Iranians
had taken out of service a total of exactly 984
machines that had been running the previous
summer.
But as Mr. Langner kept peeling back the layers,
he found more — what he calls the “dual
warhead.” One part of the program is designed
to lie dormant for long periods, then speed up the
machines so that the spinning rotors in the
centrifuges wobble and then destroy themselves.
Another part, called a “man in the middle” in the
computer world, sends out those false sensor
signals to make the system believe everything is
running smoothly. That prevents a safety system
from kicking in, which would shut down the
plant before it could self-destruct.
“Code analysis makes it clear that Stuxnet is not
about sending a message or proving a concept,”
Mr. Langner later wrote. “It is about destroying its
targets with utmost determination in military
style. ”
This was not the work of hackers, he quickly
concluded. It had to be the work of someone
who knew his way around the specific quirks of
the Siemens controllers and had an intimate
understanding of exactly how the Iranians had
designed their enrichment operations.
In fact, the Americans and the Israelis had a
pretty good idea.
Testing the Worm
Perhaps the most secretive part of the Stuxnet
story centers on how the theory of
cyberdestruction was tested on enrichment
machines to make sure the malicious software
did its intended job.
The account starts in the Netherlands. In the
1970s, the Dutch designed a tall, thin machine for
enriching uranium. As is well known, A. Q. Khan,
a Pakistani metallurgist working for the Dutch,
stole the design and in 1976 fled to Pakistan.
The resulting machine, known as the P-1, for
Pakistan ’s first-generation centrifuge, helped the
country get the bomb. And when Dr. Khan later
founded an atomic black market, he illegally sold
P-1 ’s to Iran, Libya, and North Korea.
The P-1 is more than six feet tall. Inside, a rotor of
aluminum spins uranium gas to blinding speeds,
slowly concentrating the rare part of the uranium
that can fuel reactors and bombs.
How and when Israel obtained this kind of first-
generation centrifuge remains unclear, whether
from Europe, or the Khan network, or by other
means. But nuclear experts agree that Dimona
came to hold row upon row of spinning
centrifuges.
Source: Http://www.nytimes.com/2011/01/16/world/middleeast/16stuxnet.html?pagewanted=3&_r=1
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