Possible T-Mobile data breach may affect 100 million customers — what you can do

T-Mobile MVNOs
(Image credit: T-Mobile)

Update: This breach is even worse that we thought. Click here.

A data thief claims to have stolen the information of 100 million customers from T-Mobile customers, and the company acknowledged it is investigating a possible data breach.

"We are aware of claims made in an underground forum and have been actively investigating their validity," the company told Vice Motherboard. "We do not have any additional information to share at this time."

The thief posted a For Sale sign on an online cybercriminal forum, asking 6 bitcoin (about $284,000 in U.S. dollars) for part of the purported T-Mobile data that supposedly includes 30 million Social Security numbers and driver's-license numbers. 

The seller told Vice Motherboard that the data on the other 70 million people is being sold privately. It all supposedly includes names, phone numbers, physical addresses and IMEIs (handset IDs). 

Bleeping Computer, which also saw the forum post and communicated with the seller, said the data also includes phone IMSIs (SIM card IDs), customer dates of birth and T-Mobile account PINs.

Vice Motherboard said it had confirmed that a sample of the data it saw was real. We don't know that for certain yet, but the types of customer data stolen overlap nicely with what T-Mobile admitted was swiped from its servers during an incident in March 2021, although T-Mobile said that breach involved only about 400 customers, not 100 million.

What you need to do about this

If you're a T-Mobile customer, it would be best to change your account PIN and password immediately. 

You might also want to consider subscribing to a identity-theft-protection service, as the apparent theft of Social Security numbers and dates of birth is putting a lot of people at serious risk. Just bear in mind that these services can get expensive.

Bleeping Computer noted that the post didn't mention that the data had come from T-Mobile, although the seller told both Bleeping Computer and Vice Motherboard that it had.

This is far from the first time that T-Mobile has responded to reports of a data breach. By our count, the company was hacked three different times in the past 18 months — March 2021, December 2020 and March 2020. The company was also hacked in August 2018

If you're serious about protecting your personal information, you may want to consider another wireless carrier with a better track record.

Update: Further comment from T-Mobile

In statements later Monday to Bleeping Computer, Vice Motherboard and ZDNet, T-Mobile confirmed that a breach did occur, but could not confirm what was taken and how many customers were affected.

"We have determined that unauthorized access to some T-Mobile data occurred; however, we have not yet determined that there is any personal customer data involved," said the T-Mobile statement. 

"We are confident that the entry point used to gain access has been closed, and we are continuing our deep technical review of the situation across our systems to identify the nature of any data that was illegally accessed."

The seller of the stolen data told Bleeping Computer that T-Mobile's "entire IMEI history database going back to 2004" had been stolen.

An International Mobile Equipment Identity number, or IMEI, is a unique ID number given to every handset that can access GSM-based cellular networks, such as those operated by AT&T and T-Mobile.

Read next: Uber is the latest company to investigate a serious data breach, after a hacker appeared to gain access to internal systems

Paul Wagenseil

Paul Wagenseil is a senior editor at Tom's Guide focused on security and privacy. He has also been a dishwasher, fry cook, long-haul driver, code monkey and video editor. He's been rooting around in the information-security space for more than 15 years at FoxNews.com, SecurityNewsDaily, TechNewsDaily and Tom's Guide, has presented talks at the ShmooCon, DerbyCon and BSides Las Vegas hacker conferences, shown up in random TV news spots and even moderated a panel discussion at the CEDIA home-technology conference. You can follow his rants on Twitter at @snd_wagenseil.

Read more
Globe Life insurance company logo on a cell phone in front of a monitor display the About page for the company. Shadowy hand holds the phone.
850,000 people exposed in massive insurance data breach — full names, dates of birth and SSNs
An open lock depicting a data breach
Half a million teachers hit in major data breach with SSNs, financial data and more exposed — what to do now
An open lock depicting a data breach
Massive healthcare data breach just exposed the personal info of 1 million Americans — what to do now
An open lock depicting a data breach
3.5 million hit in major law firm data breach — full names, SSNs, dates of birth, addresses and more exposed
Discord on a phone and a laptop
Reported Discord data leak disputed by third-party service RestoreCard
An open lock depicting a data breach
The top 10 data breaches of 2024
Latest in Network Carriers
Super Bowl LIX signage in New Orleans
Super Bowl 2025 — here's what the big carriers are doing to amp up their networks for the Big Game
Phones floating in the clouds showing the Helium mobile app
Helium Mobile unveils a free monthly wireless plan — here's what you need to know
Visible phone service on a smartphone with a deal tag
The best unlimited data plan just dropped 33% — but you've got to act now
Mint Mobile unlimited data deal with badge
Hurry! You've got until January 24 to cut your unlimited data bill in half at Mint Mobile
a Mint Mobile sim card envelope with a deal badge
Not a typo — Mint Mobile cuts the price of unlimited data in half for a full year
A smartphone with Visible being set up on it and a deal badge
Cellular bills are out of control — and this unlimited deal for $30 a month puts the big carriers to shame
Latest in News
Surface Laptop 7 from the front
Amazon just gave Surface Laptop 7 a 'frequently returned' label — here's what's going on
New emojis with iOS 18.4 beta release.
iOS 18.4 beta brings 8 new emoji to your iPhone — here's all the new options
23andME box
23andMe has declared bankruptcy — here's how to delete your data now
half-life alyx
Latest Half-Life 3 rumors point to a 2025 release — and maybe pigs will fly
NFL Sunday Ticket logo for YouTube
NFL Sunday Ticket 2025 pricing revealed — and it's bad news
Ben Mendelsohn in Andor season 2
'Welcome to the Rebellion' — new ‘Andor’ season 2 trailer teases a darker edge