New cyber-attack model helps hackers time the next Stuxnet

January 13, 2014 by Akshat Rathi, The Conversation

Of the many tricks used by the world's greatest military strategists, one usually works well – taking the enemy by surprise. It is an approach that goes back to the horse that brought down Troy. But surprise can only be achieved if you get the timing right. Timing which, researchers at the University of Michigan argue, can be calculated using a mathematical model – at least in the case of cyber-wars.

James Clapper, the director of US National Security, said cybersecurity is "first among threats facing America today," and that's true for other world powers. In many ways, it is even more threatening than conventional weapons, since attacks can take place in the absence of open conflict. And attacks are waged not just to cause damage to the enemy, but often to steal secrets.

Timing is key for these attacks, as the name of a common vulnerability – the zero-day attack – makes apparent. A zero-day attack refers to attacking a vulnerability in a computer systems on the same day that the vulnerability is recognised, when there is preparedness to defend against attack. That is why cyber-attacks are usually carried out as soon as a cyber- is ready and before an opponent has the time to fix its vulnerabilities.

As Robert Axelrod and Rumen Iliev at the University of Michigan write in a paper just published in the Proceedings of the National Academy of Sciences, "The question of timing is analogous to the question of when to use a double agent to mislead the enemy, where it may be worth waiting for an important event but waiting too long may mean the double agent has been discovered."

Equations are as good as weapons

Axelrod and Iliev decided the best way to answer the question of timing would be through the use of a simple mathematical . They built the model using four variables:

1. Cyber-weapons exploit a specific vulnerability.
2. Stealth of the weapon measures the chance that an enemy may find out the use of the weapon and take necessary steps to stop its reuse.
3. Persistence of the weapon measures the chance that a weapon can still be used in the future, if not used now. Or, put another way, the chance that the enemy finds out their own vulnerability and fixes it, which renders the weapon useless.
4. Threshold which defines the time when the stakes are high enough to risk the use of a weapon. Beyond the threshold you will gain more than you will lose.

Using their model, it is possible to calculate the optimum time of a cyber-attack:

When the persistence of a weapon increases, the optimal threshold increases – that is, the longer a vulnerability exists, the longer one can wait before using it.

When the stealth of a weapon increases, the optimal threshold decreases – the longer a weapon can avoid detection, the better it is to use it quickly.

Based on the stakes of the outcome, weapon must be used soon (if stakes are constant) or later (if the stakes are uneven). In other words, when the gain from an attack is fixed and ramifications are low, it is best to attack as quickly as possible. When the gain is high or low and ramifications are high, it is best to be patient before attacking.

How to plan the next Stuxnet

Axelrod and Iliev's model deserves merit, according to Allan Woodward, a cybersecurity expert at the University of Surrey, because it fits past examples well. Their model perfectly predicts timing of both the Stuxnet attack and Iran's counter to it.

Stuxnet was a worm aimed at interfering with Iran's attempts to enrich uranium to build . So, from an American perspective, the stakes were very high. The worm itself remained hidden for nearly 17 months, which means its stealth was high and persistence was low. According to the model, US and Israel should have attacked as soon as Stuxnet was ready. And indeed that is what seems to have happened.

Iran responded to this attack by targeting the workstations of Aramco, an oil company in Saudi Arabia that supplied oil to the US. Although the US called this to be the "most destructive cyber-assault the private sector has seen to date", it achieved little. However, for Iran, the result mattered less than the speed of the response. In a high stakes case, the model predicts immediate use of a cyber-weapon, which is what happened in this case, too.

Although the model has been developed for cyber-attacks, it can be equally effective in modeling cyber-defense. Also, the model need not be limited to cyber-weapons; small changes in the variables can be made so that the model can be used to consider other military actions or economic sanctions.

Just like the atomic bomb

Eerke Boiten, a computer scientist at the University of Kent, said: "These models are a good start, but they are far too simplistic. The Stuxnet worm, for example, attacked four vulnerabilities in Iran's nuclear enrichment facility. Had even one been fixed, the attack would have failed. The model doesn't take that into account."

In their book Cyber War: The Next Threat to National Security and What to Do About It, Richard Clarke and Robert Knake write:

It took a decade and a half after nuclear weapons were first used before a complex strategy for employing them, and better yet, for not using them, was articulated and implemented.

That transition period is what current cyber-weapons are going through. In that light, the simplicity of Axelrod and Iliev's model may be more a strength than a weakness for now.

Explore further: Japan developing cyber weapon: report

More information: "Timing of cyber conflict," by Robert Axelrod and Rumen Iliev. PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1322638111

Related Stories

Japan developing cyber weapon: report

January 1, 2012

Japan has been developing a virus that could track down the source of a cyber attack and neutralise its programme, the daily Yomiuri Shimbun reported Sunday.

Stuxnet was 'good idea': former CIA chief

March 2, 2012

The Stuxnet computer virus sabotage of Iran's nuclear program was a "good idea" but it lent legitimacy to the use of malicious software as a weapon, according to a former CIA director.

Iran 'mobilizing' for cyberwar with West: experts

April 26, 2012

Iran is busy acquiring the technical know-how to launch a potentially crippling cyber-attack on the United States and its allies, experts told a congressional hearing on Thursday, urging the US to step up its defensive measures.

Finnish firm says new cyber attack may have targeted Iran

July 25, 2012

A scientist claiming to work for the Atomic Energy Organisation of Iran told a Finnish cyber-security group that Tehran's nuclear programme had been the victim of a new cyber attack, the group said Wednesday.

US needs offensive weapons in cyberwar: general

October 4, 2012

The United States needs to develop offensive weapons in cyberspace as part of its effort to protect the nation from cyber attacks, a senior military official said Thursday.

Chevron says hit by Stuxnet virus in 2010

November 9, 2012

Oil giant Chevron was struck by the Stuxnet virus, a sophisticated cyber attack that tore through Iran's nuclear facilities and is believed to have been launched by the United States and Israel.

Recommended for you

Auto, aerospace industries warm to 3D printing

August 25, 2016

New 3D printing technology unveiled this week sharply increases the size of objects that can be produced, offering new possibilities to remake manufacturing in the auto, aerospace and other major industries.

World's first self-driving taxis debut in Singapore

August 25, 2016

The world's first self-driving taxis will be picking up passengers in Singapore starting Thursday.

New technology may give electric car drivers more miles per minute of charging

August 23, 2016

Researchers have designed a thin plastic membrane that stops rechargeable batteries from discharging when not in use and allows for rapid recharging.

Tesla lays claim to world's fastest production car

August 23, 2016

Tesla Motors says a new version of the Model S electric car is the quickest production car in the world from zero to 60 miles per hour.

Self-driving Uber cars to carry passenger soon in Pittsburgh

August 18, 2016

In a few weeks, Uber will start using self-driving cars to carry passengers in Pittsburgh, raising the stakes in the fast-track race to deploy autonomous vehicles.

Bags don't fly free: Charges have boosted airlines' departure performances, study finds

August 24, 2016

When most major airlines began charging flyers for checked bags in 2008, travelers grumbled. Southwest Airlines—one of the most successfully run airlines in history—even resisted and seized a new marketing slogan "bags ...