A South Australian Council says data stolen from its servers has appeared on the dark web.

Wattle Range Council has confirmed it is investigating a cyber incident involving access to some of its file drives by an unauthorised third party.

Paul Duka, Director Corporate Services, told Government News perpetrators claimed they had stolen 100Gb of data and demanded a ransom.

Council is yet to confirm the claim.

“Wattle Range Council has experienced a cyber incident involving the unauthorised access by an unknown third party to a portion of legacy computer file system,” he said.

“Currently, we are continuing our investigations into what data has been taken. If investigations indicate any personal information has been impacted, we will take steps to assess the impact and keep our stakeholders informed as required.”

In a statement last Friday Council said it had been named in a post on the dark web, alongside a sample of data.

It said the files were taken from a server containing mainly publicly available information and internal working documents.

The council says it has secured its IT environment and engaged external investigators to find out what happened.

“We have monitoring in place to detect any further developments or publication of our data and will provide further updates as required,” the statement said.

“We are working with the relevant authorities and government agencies in response to this incident to ensure all appropriate steps are taken.”

Wattle Range Mayor Des Noll told the ABC council would “never anticipate” paying ransom demands.