More than 7,000 organisations have had their email systems hacked, and Australia has issued an “advanced alert”

Australian Assistant Defence Minister Andrew Hastie warned Wednesday that more than 7,000 organisations in the country have had their email systems hacked, including Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO), and called on all relevant organisations to take immediate remedial action to fix vulnerable system vulnerabilities and, if necessary, disconnect from the Internet.

The Australian Cyber Security Centre (ACSC), part of the Australian Communications Authority, issued an “advanced alert” on Tuesday, saying it was dealing with the incident due to the large number of hacking attacks against Australian organisations, some of which have been compromised. The center also warned that many Australian organisations had not installed patches, making them more vulnerable to Hackers.

The Australian Financial Review reports that more than 7,000 Australian organisations are customers of Microsoft’s Exchange email system, including the Australian government and the Commonwealth Scientific and Industrial Research Organisation, and that some had installed patches within 24 hours of Microsoft issuing them.

Microsoft recently announced that its email system, Exchange, had been hacked, affecting tens of thousands of businesses and organizations worldwide, presumably by the China-backed group Hafnium.

Brian Krebs, a cybersecurity researcher, cited anonymous sources as saying that at least 30,000 organizations across the U.S. had been hacked by the Chinese hacker group in a weblog published on Friday. Microsoft believes the cyberattacks have been underway for months.