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Starbucks Wi-Fi 'hacked customer's laptop to mine for cryptocurrency'

The value of bitcoin has soared over the year, up more than 1000% (Jordan Mansfield/Getty Images)

The next time you settle down to use free Wi-Fi in a coffee shop, you’d better check twice.

A Starbucks outlet has been exposed for hacking into a customer’s laptop to mine cryptocurrency.

Businessman Noah Dinkin noticed there was a 10-second delay when connecting to the public Wi-Fi at a Starbucks store in Buenos Aires, Argentina.

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He noticed that bit of code – a copy of Coin Hive’s Monero-mining JavaScript – had been uploaded to his browser.

Dinkin wrote that bitcoin was the digital currency being mined, but Coin Hive, the company that provides the code for the miner, only works with Monero, a competing coin.

Starbucks says its has addressed the issue involving its free Wi-Fi (Robert Nickelsberg/Getty Images)

“Hi Starbucks, did you know that your in-store wifi provider in Buenos Aires forces a 10 second delay when you first connect to the wifi so it can mine bitcoin using a customer’s laptop?” Dinkin tweeted.

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Starbucks got back to the startup boss to say it had moved to address the issue.

“As soon as we were alerted of the situation in this specific store last week, we took swift action to ensure our internet provider resolved the issue and made the changes needed in order to ensure our customers could use Wi-Fi in our store safely,” the official Starbucks account tweeted.

A number of websites have been found to be running similar code on their own sites to covertly chase digital currencies, without the knowledge or consent of users.

Starbucks spokesman Reggie Borges told Motherboard that this appeared to be an isolated incident.

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“Last week, we were alerted to the issue and we reached out to our internet service provider – the Wi-Fi is not run by Starbucks, it’s not something we own or control,” Borges said.

“We don’t have any concern that this is widespread across any of our stores.”

Bitcoin has witnessed astonishing growth in value during the year, up more than 1000%, and one coin is now worth more than $17,400 (£13,000).