Major Australian health insurance provider Medibank Private Limited has disclosed being hit by a ransomware attack last week that resulted in a temporary service outage, which has since been resolved, according to BleepingComputer. Some of Medibank's IT network was observed to have been impacted by unusual activity consistent with a potential ransomware threat but no systems have been encrypted and no evidence indicating any theft of customer data was found, noted Medibank CEO David Koczkar. "As a further precaution, we've put in place additional security measures across our network, and we continue to work with external cybersecurity experts and the Australian Government's lead cyber agency, with our forensic investigation continuing," Medibank said in a statement. The ransomware attack against Medibank follows recent high-profile cyber incidents impacting Australia, including the theft of data from 11 million Optus clients, a third-party data breach impacting Telstra, and the exposure of a Colombian government database that included Australian Federal Police secret agent identities and operation information.