Editor’s Note: The following report is excerpted from Joseph Farah’s G2 Bulletin, the premium online newsletter published by the founder of WND. Subscriptions are $99 a year or, for monthly trials, just $9.95 per month for credit card users, and provide instant access for the complete reports.

WASHINGTON – Iran has been working on cyber warfare capabilities that security experts say are aimed at critical U.S. infrastructure systems, and could be launched in retaliation to any attack on its nuclear facilities, according to a report from Joseph Farah’s G2 Bulletin.

In addition to Iran, China and Russia also are assessed to be able to attack America’s power grid and industrial control systems, which not only are highly complex but are extremely vulnerable to cyber attacks.

One U.S. intelligence source said that the Chinese have attempted to map U.S. infrastructures, particularly the electrical grid. Another source added that the Russians have been doing the same thing and may have penetrated the U.S. electrical grid system and left behind software programs to disrupt the system.

According to the open intelligence company Lignet, Iran may have shifted from defensive to offensive cyber operations following the Stuxnet virus cyber attacks that targeted its infrastructure and nuclear facilities.

Some believe it may be working to reverse engineer the Stuxnet code to develop its own cyber weapons.

Iran blames the United States and Israel for the Stuxnet attacks. Intelligence sources say that if the U.S. decides to go to war with Iran, destructive software systems which now are “sleeping” could be activated.

These sources are concerned that cyber attackers would take control of electrical facilities, nuclear power plants or financial networks through the Internet.

One security source said that Iran poses the most serious and immediate threat to the U.S. power grid system and is in the process of heavily investing in a “cyber army” to attack America’s infrastructure – including its power grids and water and sewage systems.

“Iran is not on the top of the list of U.S. cyber adversaries, but what it lacks in capability it makes up for in intent,” said Frank Ciolluffo, director of the George Washington University Homeland Security Policy Institute at a recent House Homeland Security subcommittee hearing.

According to informed sources, extortion demands already have led to cyber attacks that have taken out power equipment in various regions outside the U.S. Origins of the cyber attacks are unknown.

The vulnerability stems not only from critical infrastructures being heavily dependent on electricity and electronics but the increasing reliance by utilities on Internet-based transmissions that have increased the vulnerability of control systems.

Just as Russia and China may be assisting Iran with developing cyber warfare capabilities against U.S. systems, there also is the increasing prospect that there is collaboration with North Korea, which now is assessed by intelligence sources to be developing cyber warfare capabilities.

Given the prospect that Iran is investing in cyber warfare capability to attack U.S. infrastructure, Lignet warned that unless the U.S. and its allies devise adequate critical infrastructure systems protection, there is the increasing prospect that Tehran will conduct “remote attacks to inflict significant damage to the U.S. homeland by exploiting serious Internet security vulnerabilities.”

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