The Australian Cyber Security Centre (ACSC) has pointed the finger at an Iranian criminal group in relation to the recent theft of ship designs from a top local naval ship manufacturer.

The Western Australia shipbuilder Austal, which currently holds contracts with the US Navy, earlier this month announced its systems had been breached by “an unknown offender”.

The hack left staff email addresses and phone numbers compromised.

Building maps for ships were also seen for sale on the dark web following the breach.

It is believed the incident occurred in mid-October.

Austal only notified the ASX of the incident after it had appeared on social media.

“Austal Australia’s Information Systems and Technology (IS&T) team have restored the security and integrity of the company’s data systems and have implemented, and continues to implement, additional security measures to prevent further breaches,” the company said in a statement dated 1 November.

“A small number of stakeholders who were potentially directly impacted have been informed. The data breach has had no impact on Austal’s ongoing operations.

“There is no evidence to date to suggest that information affecting national security nor the commercial operations of the company have been stolen: ship design drawings which may be distributed to customers and fabrication sub-contractors or suppliers are neither sensitive nor classified.”

Austal also noted that it “has not and will not respond to extortion attempts”.

Now, less than two weeks after Austal first announced the breach, the ACSC has revealed the attack was most likely the work of a criminal group in Iran.

ABC News reported the story on Tuesday, quoting a spokesperson from the Department of Home Affairs who confirmed the malicious actor sought to profit from the attack.

While the ACSC did not infer the criminal group was connected to the Iranian government, the hack occurred just days after Prime Minister Scott Morrison announced the government would be reviewing its support for the Iran nuclear deal.

The United States has also listed Iran as a ‘leading cyberspace adversary’, alongside the likes of Russia, China and North Korea.

Earlier this year, Austal lost a $3 billion contract with the Australian Navy to build the next generation of offshore patrol boats.