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Starbucks Wi-Fi used customer’s computer to mine cryptocurrency

The coffeehouse chain says it doesn't think this is a widespread issue.


Phillip Tracy


Posted on Dec 12, 2017   Updated on May 22, 2021, 8:14 am CDT

An unsettling incident at a Starbucks in Argentina shows how far people will go to get their hands on cryptocurrency, the decentralized form of digital money that has skyrocketed in value over the last few months.

Noah Dinkin, CEO of email marketing firm Sensul, connected his laptop to Starbucks’ free public Wi-Fi, as millions of other coffee drinkers have done in the past. But when he pulled up his browser’s source code, he discovered something out of the ordinary: The Wi-Fi network was exploiting his laptop to mine cryptocurrency.

“Hi @Starbucks @StarbucksAr 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? Feels a little off-brand,” the concerned customer wrote on Twitter on Dec. 2.

While Dinkin said his computer was being used to mine Bitcoin, it seems more likely that it was mining the cryptocurrency Monero, since the company providing the JavaScript code only works with the rival currency.

To its credit, the official Starbucks Coffee Twitter account responded (though nine days later), claiming it fixed the problem as soon as it was notified.

In a statement to Motherboard, the company blamed its Wi-Fi provider and assured the incident was limited to one location.

“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,” Starbucks spokesperson Reggie Borges said. “We want to ensure that our customers are able to search the internet over Wi-Fi securely, so we will always work closely with our service provider when something like this comes up. We don’t have any concern that this is widespread across any of our stores.”

Hiding source code in websites to mine cryptocurrency isn’t as uncommon as you may think. It’s becoming a concerning trend as the value of Bitcoin continues to explode. Aside from exploiting people’s machines without their permission, there are a number of problems with in-browser cryptocurrency mining. The most pressing issue is the amount of energy needed to support digital currency.

Current estimates say the total energy used to mine Bitcoin is comparable to the amount of energy used by New Zealand. And as Newsweek points out, it could, within five years, consume as much energy as the entire world. Bitcoin mining also impacts users by feeding off their computer’s processing resources.

If you notice your computer slowing down when you’re connected to public Wi-Fi, you may want to take a peek at what’s going on behind the scenes.

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*First Published: Dec 12, 2017, 10:25 pm CST