Is Stuxnet a cyber weapon aimed at an Iranian nuclear site?

There have been reports over the past weeks about Stuxnet, a new malware system that experts say is designed to seek out and damage certain kinds kind of industrial sites. Some argue that it has already hit and damaged its target.

The Christian Science Monitor published a good overview earlier this week.

“Cyber security experts say they have identified the world’s first known cyber super weapon designed specifically to destroy a real-world target – a factory, a refinery, or just maybe a nuclear power plant.

The cyber worm, called Stuxnet, has been the object of intense study since its detection in June. As more has become known about it, alarm about its capabilities and purpose have grown. Some top cyber security experts now say Stuxnet’s arrival heralds something blindingly new: a cyber weapon created to cross from the digital realm to the physical world – to destroy something.

At least one expert who has extensively studied the malicious software, or malware, suggests Stuxnet may have already attacked its target – and that it may have been Iran’s Bushehr nuclear power plant, which much of the world condemns as a nuclear weapons threat.”

The computer security company Symantec has been tracking it for a while and reported back in August that Stuxnet differs from typical Windows oriented in that it is designed to infect the Programmable Logic Controllers used in industrial control systems.

“As we’ve explained in our recent W32.Stuxnet blog series, Stuxnet infects Windows systems in its search for industrial control systems, often generically (but incorrectly) known as SCADA systems. Industrial control systems consist of Programmable Logic Controllers (PLCs), which can be thought of as mini-computers that can be programmed from a Windows system. These PLCs contain special code that controls the automation of industrial processes—for instance, to control machinery in a plant or a factory. Programmers use software (e.g., on a Windows PC) to create code and then upload their code to the PLCs.

Previously, we reported that Stuxnet can steal code and design projects and also hide itself using a classic Windows rootkit, but unfortunately it can also do much more. Stuxnet has the ability to take advantage of the programming software to also upload its own code to the PLC in an industrial control system that is typically monitored by SCADA systems. In addition, Stuxnet then hides these code blocks, so when a programmer using an infected machine tries to view all of the code blocks on a PLC, they will not see the code injected by Stuxnet. Thus, Stuxnet isn’t just a rootkit that hides itself on Windows, but is the first publicly known rootkit that is able to hide injected code located on a PLC.”

Symantec’s analysis of where Stuxnet has been found supports the theory that it was intended for targets in Iran, as the following map illustrates.

Security expert Frank Rieger writes that Stuxnet is exceptionally well designed and written and starts out on infected USB sticks.

“stuxnet is a so far not seen publicly class of nation-state weapons-grade attack software. It is using four different zero-day exploits, two stolen certificates to get proper insertion into the operating system and a really clever multi-stage propagation mechanism, starting with infected USB-sticks, ending with code insertion into Siemens S7 SPS industrial control systems. One of the Zero-Days is a USB-stick exploit named LNK that works seamlessly to infect the computer the stick is put into, regardless of the Windows operating system version – from the fossil Windows 2000 to the most modern and supposedly secure Windows 7.”

Rieger further argues that evidence suggests that Stuxnet is targeted not at Iran’s Bushehr reactor but at the uranium enrichment plant in Natanz and has already achieved success. To support the last conclusion, he sites a note on Wikileaks about a “a serious, recent, nuclear accident at Natanz” in July 2010.

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