If you're a U.S. security professional and you think foreign attackers are the biggest threat to your organization, you've got another think coming, according to two new studies.

According to separate research reports published yesterday, the United States is the most common source of attacks, and that trend could continue as attackers find ways to exploit networks here at home.

According to data published by research firm SecureWorks, the U.S. is the most common source of cyber attacks on the planet. This year alone, some 20.6 million attempted attacks have originated from computers within the U.S., the company says.

China ran second, with 7.7 million attempted attacks emanating from computers within its borders. Brazil was third with about 166,987 attempted attacks. Russia, often viewed as the most frequent hideout of online attackers, finished sixth with a paltry 130,572.

"These findings illustrate the ineffectiveness of simply blocking incoming communications from foreign IP addresses as a way to defend your organization from cyber attacks," SecureWorks says. "Many hackers hijack computers outside their borders to attack their victims."

The Georgia/Russia cyber conflict was a perfect example of this, SecureWorks says. Many of the Georgian IT staff members thought that by blocking Russian IP addresses, they would be able to protect their networks. However, many of the Russian attacks were actually launched from IP addresses in Turkey and the United States, and Georgian systems ended up being hit hard.

In a separate report by the SANS Institute, researcher Maarten Van Hoorenbeeck wrote yesterday that stolen data is increasingly being stored on networks in the U.S. and Europe. This is a shift from the past, in which criminals generally transferred stolen data to networks in other geographic jurisdictions, he notes.

After further study, Van Hoorenbeeck found that the stolen data was, in some cases, being tunneled through U.S. and European networks using anonymization services, which may actually be tougher for law enforcement to crack than overseas networks.

"Certain hosts started tunneling data to the network of an Indiana based provider of anonymity services, SecureIX," Van Hoorenbeeck writes. "This provider allows users to set up a PPTP VPN connection to its servers, then hiding all their traffic behind a SecureIX IP address.

"The service is intended for well-meaning users who wish to remain anonymous while surfing. However, the for-a-fee SecureIX service also allows users to run services through such IP address. Hosts compromised by the attackers were configured to ship data to a specific port on a SecureIX IP, from where it was tunneled back to the attacker."

Such anonymization services are not entirely safe for attackers, Van Hoorenbeeck says. "In the case of a prosecution, SecureIX would disclose the data it has on [its users]," he notes.

While it is still operational, SecureIX has announced that its service is up for sale, Van Hoorenbeeck says. And just two weeks after the for-sale sign was posted, all hostnames previously pointing to SecureIX suddenly resolved to the IP address space of Relakks, which provides the same services from Sweden.

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