Starbucks urges customers to beef up their passwords after hackers gain access to customer accounts through the mobile payment app.

That app allows customers to pay at the register with their smartphone. Their account is automatically reloaded with cash from their credit card, bank or PayPal.  Hackers are taking over the account and repeatedly siphoning the money as it reloads.

These thefts were first reported by consumer advocate Bob Sullivan.

Disabling the automatic reload function may not be enough, because a clever hacker can simply enable it again.  Disabling the mobile app altogether is more extreme but will shut them out.

Starbucks tells CNN, the company itself has not been hacked and no consumer data has been exposed.  Starbucks believes these account takeovers are probably due to weak password protection.

The chain recommends customers keep a close eye on their account activity, but promises all fraudulent charges will be reimbursed.