A major ransomware attack, which hit servers across Europe and the US, has reached Australia.

On Wednesday, Australian Cyber Security Minister Dan Tehan issued an urgent warning to small businesses to update their cyber security.

Hobart’s Cadbury factory has been affected, with its parent company saying they are working to resolve the situation as quickly as possible.

Cyber security journalist Stilgherrian has told Ross and John if you see the ransom message, shut your computer down and call for help.

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Known affected businesses:

• Cadbury
• DLA Piper (Statement)

A 3AW listener has told Neil Mitchell courier service TNT could also have been effected by the attack.

If you have been affected, contact the Australian Cyber Security Centre on 1300 CYBER1 or visit acsc.gov.au