The White House confirmed on Monday that it thwarted an attempted cyber attack but declined to discuss where it originated from after a media report identified China as the culprit.
The conservative Washington Free Beacon reported Sunday that hackers believed to be associated with the Chinese government had breached a computer system used by the White House Military Office.
A White House official confirmed an attempted cyber attack against an unclassified network, but declined to comment on its origins or whether it was at the military office.
"These types of attacks are not infrequent and we have mitigation measures in place," the official said.
"In this instance the attack was identified, the system was isolated, and there is no indication whatsoever that any exfiltration of data took place," the official said in a statement to The Hill. "Moreover, there was never any impact or attempted breach of any classified system."
Citing defense and intelligence officials familiar with the breach, the Free Beacon reported that hackers breached a computer system used by the White House Military Office in September. The report said the office is in charge of some of the government's most sensitive communications, such as nuclear commands.
China is believed to be behind some of the biggest hacking attacks aimed at the U.S. government and companies. Last year, the U.S.-China Economic and Security Review Commission reported that hackers likely tied to the Chinese military had interfered with U.S. government satellites, according to Bloomberg.
Google revealed in 2010 that its infrastructure had been hit by an attack stemming from China and said third parties had accessed Gmail accounts belonging to Chinese human-rights activists.