In 2011, more than 45,000 cyberattacks were attempted and last year the number grew four-fold.
"We see a myriad of attacks," from hackers trying to enter the network to "advanced, persistent attacks out there that we continue to defend against," Air Force Gen. William M. Fraser III, commander of TRANSCOM, told the Senate Armed Services Committee last week.
TRANSCOM is responsible for moving troops and supplies around the world. It relies heavily on commercial partners, which account for about 70 percent of personnel and cargo transport.
Fraser said 90 percent of the command's distribution and deployment transactions are conducted over unclassified and commercial systems. Those systems lack the safeguards of more secure government and military networks.
"It is an area that we have significant concern (about) but we have taken a lot of action (to institute safeguards) and not just in one area. We are taking a holistic approach as we work this specific issue."
TRANSCOM, he said, is working with commercial and inter-agency partners to strengthen the networks.