Congress has launched a probe into cyber attacks on White House computer networks that are believed to have exposed personally identifiable information of U.S. citizens and official meetings with ambassadors, according to a letter sent to President Obama by a Senate investigatory committee.

Lawmakers are attempting to determine the extent of a recent breach reported to have been committed by Russian hackers in 2014. While the White House initially downplayed the extent of the information accessed by these cyber criminals, investigators say the breach may have been more widespread than previously believed.

The White House has revealed few details about the attack, but it is believed the 2014 breach is just one of several attacks by hackers in recent months.

Sen. John Thune (R., S.D.), chairman of the Senate’s Committee on Commerce, Science and Transportation, is now seeking to determine the full extent of the breach and to discern how much personal information the hackers accessed.

“Though the hackers do not appear to have accessed any classified information, the unclassified computer system reportedly contains a great deal of sensitive information, such as schedules, policy discussions, and emails you sent and received, including exchanges with ambassadors,” Thune wrote in a letter to Obama on April 30.

The system breached by hackers also contained information about Americans who have been to the White House, compromising their social security numbers and other personal information.
It is unclear whether the White House has contacted these individuals to let them know that their information was potentially accessed.

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