The credentials were stored in such a way that anyone with access to the phone can see the passwords and usernames by connecting the phone to a PC. No jailbreaking of the phone is necessary. And that clear text also displays an extensive list of geolocation tracking points (latitude, longitude), a treasure trove of security and privacy gems for anyone who steals the phone.
The vulnerability was first discovered by security researcher Daniel Wood, who published his findings online for the security community after repeatedly not having success when attempting to contact Starbucks.
The coffee company tells Computerworld that it has "security measures in place now related to that". However, Wood tells The Verge that anything Starbucks does on its end "would not matter" because the vulnerability lies within the app itself.
Potential criminals would still need to physically have the phone to attain any user information, and the only information available would be user names, passwords and location data, but users of the app who had the "auto replenish" feature on would enable criminals to continually add money to the app to make Starbucks purchases.
Update: Starbucks has issued a statement acknowledging the issue and promising an expedited updated for the company's iOS app.
We’d like to be clear: there is no indication that any customer has been impacted by this or that any information has been compromised. Regardless, we take these types of concerns seriously and have added several safeguards to protect the information you share with us. To protect the integrity of these added measures, we are unable to share technical details but can assure you that they sufficiently address the concerns raised in the research report.
Out of an abundance of caution, we are also working to accelerate the deployment of an update for the app that will add extra layers of protection. We expect this update to be ready soon and will share our progress here. While we are working on the update, we would like to emphasize that your information is protected and that you should continue to feel confident about the integrity of our iOS app.