Optus intends to defend itself against claims it failed to protect customer details during a cyber attack on its database two years ago.
The Australian Communications and Media Authority (ACMA) has lodged the action, alleging that the telecommunications company breached the Telecommunications (Interception and Access) Act 1979.
The Federal Court will hold a directions hearing at a date yet to be advised.
Compromised personal data
The September 2022 cyber attack compromised the personal information of more than 9 million Optus customers, exposing passport numbers, driver's licence details and personal addresses online.
ACMA's action, filed on Monday, claims that Optus failed to protect the confidentiality of its customers' information from unauthorised interference or access as required by law.
Optus has stated its intention to defend the allegations but has declined to comment further due to the ongoing legal proceedings.
The data breach spurred Prime Minister Anthony Albanese to call for stricter cyber security laws and drew criticism from federal authorities.
Optus CEO Kelly Bayer Rosmarin resigned a year after the breach, which continues to have significant repercussions.
On September 20, 2022, Optus detected suspicious activity in its servers and publicly disclosed the breach 24 hours later.
The company confirmed that cybercriminals had accessed its customer database, potentially compromising up to 9.8 million accounts.
Hackers demanded a ransom
Optus shut down the attack and reported it to Australian authorities, prompting investigations by the Australian Federal Police and ACMA.
As details of the attack emerged, it was revealed that hackers likely obtained passport and driver's licence numbers for 2.8 million people.
The attackers demanded a ransom of $1 million in cryptocurrency, threatening to publish the data of 10,000 Optus customers daily. They later retracted the threat and apologised for leaking the data of 10,200 Australians.
Optus has apologised for the breach through full-page advertisements in major newspapers and has taken steps to regain customer trust.
The company has also reimbursed customers for the cost of replacing identity documents and worked with authorities to protect affected individuals. Despite these efforts, Home Affairs Minister Clare O'Neil criticised Optus for leaving the "window open" for cybercriminals.
ACMA has already fined Optus $1.5 million over the breach and has lodged documents in the Federal Court.
Law firm Slater and Gordon has filed a class action on behalf of more than 100,000 registered participants.