Following the recent confirmation by a senior intelligence officer with the U.S. Cyber Command that the Pentagon systems and networks are constantly under cyber attacks and cyber espionage attempts that can be traced back to China, the news that the (probably) same attackers targeted the White House military office network shouldn't come as a surprise.
According to unnamed sources, the attackers managed to get into one of the U.S. government's most sensitive computer networks, but it seems that protective measures allowed the breach to be quickly detected and blocked.
The White House Military Office (WHMO) "provides military support for White House functions, including food service, Presidential transportation, medical support and emergency medical services, and hospitality services," but also "oversees policy related to WHMO functions and Department of Defense assets" and "all military operations aboard Air Force One on Presidential missions worldwide," which includes communication with intelligence and military officials, as well as the communication of potential strategic nuclear commands.
Continued : http://www.net-security.org/secworld.php?id=13698
Also: Chinese Hackers Take Bad Trip to White House; Nuclear Command System Among Targets