Hackers are breaking into AT&T email accounts to steal cryptocurrency

AT&T says cybercriminals exploited an API issue to take control of victims' email addresses

Unknown hackers are breaking into the accounts of people who have AT&T email addresses, and using that access to then hack into the victim’s cryptocurrency exchange’s accounts and steal their crypto, TechCrunch has learned.

At the beginning of the month, an anonymous source told TechCrunch that a gang of cybercriminals have found a way to hack into the email addresses of anyone who has an att.net, sbcglobal.net, bellsouth.net and other AT&T email addresses.

According to the tipster, the hackers are able to do that because they have access to a part of AT&T’s internal network, which allows them to create mail keys for any user. Mail keys are unique credentials that AT&T email users can use to log into their accounts using email apps such as Thunderbird or Outlook, but without having to use their passwords.

With a target’s mail key, the hackers can use an email app to log into the target’s account and start resetting passwords for more lucrative services, such as cryptocurrency exchanges. At that point it’s game over for the victim, as the hackers can then reset the victim’s Coinbase or Gemini account password via email.

The tipster provided a list of alleged victims. Two of the victims replied, confirming they have been hacked.

AT&T spokesperson Jim Kimberly said that the company “identified the unauthorized creation of secure mail keys, which can be used in some cases to access an email account without needing a password.”

“We have updated our security controls to prevent this activity. As a precaution, we also proactively required a password reset on some email accounts,” the spokesperson said, forcing the account owners to reset their passwords.

AT&T declined to say how many people have been hit in this wave of hacks. “This process wiped out any secure mail keys that had been created,” the spokesperson added.

One victim told TechCrunch that hackers stole $134,000 from his Coinbase account. The second victim said that “it has been happening repeatedly since November 2022 — probably 10 times at this point. I notice it has been done when my Outlook client fails to ‘connect’ and I quickly login to my [AT&T] site and delete their key and create a new one.”

“Very frustrating because it is obvious that the ‘hackers’ have direct access to the database or files containing these customer Outlook keys, and the hackers don’t need to know the user’s AT&T website login to access and change these outlook login keys,” the victim added.

Also, several people with AT&T and other related email addresses said on Reddit that they have been hacked.

“Hello, my email was compromised back in March of this year and I have done everything I can to reset password, security questions, etc but occasionally I’m still getting emails that a secure mail key has been created on my account without my knowledge,” one user wrote. “They would even delete the email notification so I don’t see it but I recently changed to another email for profile updates so they don’t have access. This sounds like someone still has access to my account but how?”

Another person wrote: “I’ve had the same issue for months and just started again, password wasn’t changed but account locked out and a Mail Key keeps being created somehow.”

The tipster claims that the hackers can “reset any” AT&T email account, and that they have made between $15 and $20 million in stolen crypto. (TechCrunch could not independently verify the tipster’s claim.)

TechCrunch has seen a screenshot apparently coming from a Telegram group chat, where one of the hackers claims that the gang “have the entire AT&T employee database,” which allows them to access an internal AT&T portal for employees called OPUS.

“Only thing we are missing is a certificate, which is the last key to accessing the [AT&T] VPN servers,” the hacker wrote in the Telegram channel, according to the screenshot.

The tipster said that the gang now has access to AT&T’s internal VPN.

Kimberly, the AT&T’s spokesperson, denied that the hackers had any access to internal company systems. “There was no intrusion into any system for this exploit. The bad actors used an API access.”

Do you have more information about these hacks against AT&T email users? Or other similar hacks? We’d love to hear from you. You can contact Lorenzo Franceschi-Bicchierai securely on Signal at +1 917 257 1382, or via Wickr, Telegram and Wire @lorenzofb, or email lorenzo@techcrunch.com. You can also contact TechCrunch via SecureDrop.