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"This finding is worrying because of the very 'open' nature of most default social media settings, sometimes set by the social network operator to permit the widest possible use of your information," ESET senior security researcher Stephen Cobb wrote in a blog post discussing the findings. "It is hard to think that everyone who leaves the default settings in place is aware of the implications."
The survey also found that one third of social media users had received suspicious messages via social media, and more than one in five had encountered malware or links to malware on social networks.
Half of employed adults who have work-issued devices say they check their social media accounts from those devices, potentially putting their company at risk.
Fully 28 percent of social media users said that one or more of their social media accounts had been hacked -- for more than half of those people, the breach had occurred this year. Those aged 18-34 (61 percent) were far more likely than those aged 35+ (46 percent) to have had a social media account hacked this year.
Still, only one quarter of social media users say they've received any online safety training.