Hackers associated with the Chinese government had gained entry a number of times, into computer systems of defence contractors, US airlines, technology companies and those involved in the movement of US troops and military equipment, a US Senate panel found, Reuters reported.
The revelation came from an over a year long probe by the Senate Armed Services Committee. The probe, which concluded in March, was made public yesterday. It found the military's US Transportation Command, or Transcom, had known of at least 20 such cyber intrusions within a single year.
The investigation also uncovered gaps in reporting requirements as also a lack of information sharing among US government entities, which in turn, left the military largely in the dark about computer systems compromises at its contractors.
The committee chairman, Democratic senator Carl Levin of Michigan, releasing the report said, these peacetime intrusions into the networks of key defense contractors were further evidence of China's aggressive actions in cyberspace.
According to Cybersecurity expert Dmitri Alperovitch, chief technology officer with the security firm Crowdstrike, China had for years shown a keen interest in the logistical patterns of the US military.
The investigation had focused on the ability of the US military to seamlessly tap civilian air, shipping and other transportation assets for tasks including troop deployments and the timely arrival of supplies from food to ammunition to fuel.
The companies typically did not have the level of defence against hackers as major weapons makers or the military itself.
Through the breaches, the hackers had gained insight into military logistics and a foothold that could be used to disrupt operations, the investigation revealed, Bloomberg reported.
While public attention had focused on the hacking of companies like JP Morgan Chase & Co and Home Depot, the US Defence Department was faced with persistent digital incursions aimed at stealing military secrets and potential disruption of vital computer networks.
Private airlines provided over 90 per cent of Defence Department personnel movement and in excess of a-third of bulk cargo capability, the report said.
The committee had no idea whether hackers from China or other governments still continued to target the networks of military transportation contractors, senator Carl Levin, a Michigan Democrat and chairman of the panel, told reporters in Washington today.
The Defence Department said in a statement that it took the findings ''very seriously'' and that it was addressing ''gaps'' identified in the report.
''This is a very high priority for the department,'' it added.