The federal government admits it still doesn't know who managed to hack top secret technical information about new fighter jet and navy vessels more than a year ago.
But Defence Industry Minister Christopher Pyne insists the data obtained from an Adelaide defence contractor was only commercially sensitive and not "classified" military information.
The hack included information on the F-35 Joint Strike Fighter, C130 Hercules aircraft and the P-8 Poseidon surveillance aircraft.
"I don't know who did it... it could be one of a number of different actors. It could be a state actor, a non-state actor," Mr Pyne told ABC radio on Thursday.
"It could be someone who was working for another company."
Australian Signals Directorate incident response manager Mitchell Clarke told a conference in Sydney on Wednesday the hackers targeted a small "mum and dad type" aerospace engineering company with about 50 employees in July 2016.
The firm was subcontracted four levels down from defence contracts and had only one IT person.
Mr Clarke said the information hacked on the new Navy ships included a diagram in which you could zoom in on the captain's chair and see that it was one metre away from the navigation chair.
Mr Pyne says the incident is a reminder for businesses to take their cyber security very seriously.
"This attack ... is a salutary reminder to everyone in the industry and the government about this kind of behaviour going on," he said.
"Fortunately, the data that was taken was commercial data, not military data, but it's still very serious and we will get to the bottom of it."
Mr Pyne warns cyber attacks of this type are being attempted all the time and conceded some will be successful.
He rejected claims the federal government was to blame for the small enterprise having "lax" cyber security.
The prime minister's adviser on cyber security Alastair MacGibbon says there is a range of ways the attacker could have got in, including default passwords.
"It's a third-party supply chain issue," he told ABC TV.
"I suspect defence contractors around the country will be looking at their systems; I hope they are."
