The security expert contacted dozens of UK and US-based firms to test how they would handle a “right of access” request made in someone else’s name.
In each case, he asked for all the data that they held on his fiancee.
In one case, the response included the results of a criminal activity check.
Other replies included credit card information, travel details, account logins and passwords, and the target’s full US social security number.
University of Oxford-based researcher James Pavur has presented his findings at the Black Hat conference in Las Vegas.
It is one of the first tests of its kind to exploit the EU’s General Data Protection Regulation (GDPR), which came into force in May 2018. The law shortened the time organisations had to respond to data requests, added new types of information they have to provide, and increased the potential penalty for non-compliance.
“Generally if it was an extremely large company – especially tech ones – they tended to do really well,” he told the BBC.
“Small companies tended to ignore me.
“But the kind of mid-sized businesses that knew about GDPR, but maybe didn’t have much of a specialised process [to handle requests], failed.”
He declined to identify the organisations that had mishandled the requests, but said they had included:
– a UK hotel chain that shared a complete record of his partner’s overnight stays
– two UK rail companies that provided records of all the journeys she had taken with them over several years
– a US-based educational company that handed over her high school grades, mother’s maiden name and the results of a criminal background check survey.
Mr Pavur has, however, named some of the companies that he said had performed well.