Hackers working for the Russian government are believed to have been responsible for last fall's breach of the White House' unclassified computer network, according to CNN.

In October 2014, a White House official told the Washington Post that "activity of concern" had been identified "on the unclassified Executive Office of the President network."

While the White House says no classified systems were accessed, CNN reports that the hackers were able to access some sensitive information, including real-time, non-public details of President Obama's schedule.

The CNN report calls the breach "among the most sophisticated attacks ever launched against U.S. government systems."

Bloomberg News yesterday reported that an anonymous source said an analysis of the malware involved, along with other evidence, "show certain characteristics known to be used by criminal hackers working under the sponsorship of the Russian government."

The same source said the attack was likely launched in retaliation for U.S. sanctions.

CNN reports that the hackers first breached State Department computers, then launched a phishing email from a compromised State Department email account to gain access to the White House network.

In a conference call with reporters, Russian government spokesman Dmitry Peskov denied the charges, saying, "It has become a kind of sport to blame everything on Russia."

Caspida CEO Muddu Sudhakar told eSecurity Planet by email that all U.S. government agencies should now act on the assumption that Russia, China, North Korea, Iran and others are actively targeting their networks. "We should assume by now that other countries have replicated NSA's capabilities and have similar organizations that are constantly attacking U.S. interests," he said.

"We need the next level of cyber defense, which will provide early breach detection proactively and in real time, while operating continuously 24/7," Sudhakar added. "We are in a new age of cyber attacks, and as such, need to drastically improve our security measures."

And AVG Technologies CTO Yuval Ben-Itzhak said by email that the accusation that Russian hackers were responsible for the breach is an extremely serious one. "This is a direct attempt to access the heart and soul of the American political system, and the digital data held within it," he said.

"Organizations are only as secure as their weakest link and, as has been the case for many years, this link will always be people," Ben-Itzhak added. "Social engineering or 'the human link' will continue to be a significant challenge for the security industry. You can implement the best technologies available but if an authorized person is making the wrong decisions and letting someone in, the technology can break down very easily."

A recent eSecurity Planet article offered advice on leveraging security awareness training to fend off social engineering attacks.

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