"Given there are a range of variants in the infection, we recommend that once someone has run the tool they go back to the website to test if they are still infected and try another tool," Matthews said.

He added that ACMA was working with internet service providers to help inform their customers that may be infected with the DNSChanger malware so that most of the infected internet users will have got rid of the malware by 9 July.

Got a security tip-off? Contact Hamish Barwick at hamish_barwick at idg.com.au

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