The Australian Federal Police has urged St George and Shire internet users to do a cyber cull to protect themselves from cyber criminals, fraudsters, organised crime gangs and sex offenders.
The AFP say social media users are posting too much personal and professional information, and some have become easy targets for criminals.
AFP Assistant Commissioner Justine Gough said the advice was for all social media users, young and old.
"This advice is not just for younger Australians, but for government employees, those who worked in sensitive areas, and single parents who revealed the ages of their children on dating websites," Assistant Commissioner Gough said.
"You wouldn't walk up to a stranger and let them know your security clearance or that you work in payroll in your organisation.
"You wouldn't give a stranger your phone number, your date of birth or provide them with a photo album of your children.
"But too many Australians are essentially doing this by posting this information online and not turning on strict privacy controls. Pause before you post. Ask yourself, 'Do you really need to reveal your personal details?'"
Assistant Commissioner Gough said some Australians could be targeted because of their position within a company, government agency or university.
"They may pretend to be an employer or recruiter wanting to hire and groom a victim to understand what access or knowledge they have within an organisation," she said.
In other cases, people are putting their financial security at risk.
"Criminals are harvesting information, stealing identities and then stealing victims' money, or taking out credit cards in victims' names. In some cases, criminals have been able to obtain personal information and access financial accounts," she said.
"People who are selling second-hand goods on websites and provide their mobile phone number can leave themselves vulnerable to phishing attacks. Personal information is a valued commodity for criminals, who can sell this to others in forums on the dark web.
"We also know child sex offenders have looked for victims by targeting single parents on dating websites.
"We are also urging all parents to think twice about posting photographs of their kids. Some platforms do not automatically remove geolocation data from images taken on mobile phones, allowing for identifying where you work, your home address, or other private locations.
"The online world allows criminals to steal from, and manipulate victims, from across the globe."
Online users should review location, privacy settings and parental controls and review and turn off location settings, such as GPS, when unnecessary. Ensure privacy settings are secure and set to 'Friends only' or 'Private'. Research parental controls to see if they are suitable for your family.
Offensive, illegal or harmful content online - including child sexual abuse material - can be reported to eSafety for takedown.
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