Optus’ nearly 11 million customers should be “extra vigilant” over the coming weeks of incoming calls, texts and emails as well as regularly check in with their banks, cybersecurity experts warn after a massive hack of Optus that has compromised the addresses, drivers licences and passports of its users.

The telco alerted customers of the attack on Thursday – a day after the hack was first identified – and said it had shut down the attack. It is working with the Australian Federal Police, Australian Signals Directorate, Office of the Australian Information Commissioner to mitigate risk and find the culprit.