• Home
  • Cyber Crime
  • Cyber warfare
  • APT
  • Data Breach
  • Deep Web
  • Digital ID
  • Hacking
  • Hacktivism
  • Intelligence
  • Internet of Things
  • Laws and regulations
  • Malware
  • Mobile
  • Reports
  • Security
  • Social Networks
  • Terrorism
  • ICS-SCADA
  • POLICIES
  • Contact me
MUST READ

Seychelles Commercial Bank Reported Cybersecurity Incident

 | 

Microsoft uncovers macOS flaw allowing bypass TCC protections and exposing sensitive data

 | 

U.S. CISA adds Cisco ISE and PaperCut NG/MF flaws to its Known Exploited Vulnerabilities catalog

 | 

Critical WordPress Post SMTP plugin flaw exposes 200K+ sites to full takeover

 | 

Scattered Spider targets VMware ESXi in using social engineering

 | 

China-linked group Fire Ant exploits VMware and F5 flaws since early 2025

 | 

Allianz Life data breach exposed the data of most of its 1.4M customers

 | 

SECURITY AFFAIRS MALWARE NEWSLETTER ROUND 55

 | 

Security Affairs newsletter Round 534 by Pierluigi Paganini – INTERNATIONAL EDITION

 | 

Law enforcement operations seized BlackSuit ransomware gang’s darknet sites

 | 

Arizona woman sentenced for aiding North Korea in U.S. IT job fraud scheme

 | 

Operation CargoTalon targets Russia’s aerospace with EAGLET malware,

 | 

Unpatched flaw in EoL LG LNV5110R cameras lets hackers gain Admin access

 | 

Koske, a new AI-Generated Linux malware appears in the threat landscape

 | 

Mitel patches critical MiVoice MX-ONE Auth bypass flaw

 | 

Coyote malware is first-ever malware abusing Windows UI Automation

 | 

SonicWall fixed critical flaw in SMA 100 devices exploited in Overstep malware attacks

 | 

DSPM & AI Are Booming: $17.87B and $4.8T Markets by 2033

 | 

Stealth backdoor found in WordPress mu-Plugins folder

 | 

U.S. CISA adds CrushFTP, Google Chromium, and SysAid flaws to its Known Exploited Vulnerabilities catalog

 | 
  • Home
  • Cyber Crime
  • Cyber warfare
  • APT
  • Data Breach
  • Deep Web
  • Digital ID
  • Hacking
  • Hacktivism
  • Intelligence
  • Internet of Things
  • Laws and regulations
  • Malware
  • Mobile
  • Reports
  • Security
  • Social Networks
  • Terrorism
  • ICS-SCADA
  • POLICIES
  • Contact me
  • Home
  • Breaking News
  • Cyber Crime
  • Data Breach
  • T-Mobile suffered a new data breach

T-Mobile suffered a new data breach

Pierluigi Paganini December 29, 2021

T-Mobile discloses a new data breach that impacted a “very small number of customers” who were victim of SIM swap attacks.

T-Mobile has suffered another security breach, threat actors gained access to the accounts of “a small number of” customers.’

According to The T-Mo Report, which viewed T-Mobile internal documents, there was “unauthorized activity” on some customer accounts. The attackers viewed customer proprietary network information (CPNI) and carried out SIM swapping attacks on a small number of customers.

“Affected customers fall into one of three categories. First, a customer may have only been affected by a leak of their CPNI.” reported The T-Mo Report. “The second category an affected customer might fall into is having their SIM swapped.” “The final category is simply both of the other two. Affected customers could have had both their private CPNI viewed as well as their SIM card swapped.”

Customer proprietary network information exposed in the attack could’ve included billing account name, phone numbers, number of lines on the account, account numbers, and rate plan info.

“We informed a very small number of customers that the SIM card assigned to a mobile number on their account may have been illegally reassigned or limited account information was viewed. Unauthorized SIM swaps are unfortunately a common industry-wide occurrence, however this issue was quickly corrected by our team, using our in-place safeguards, and we proactively took additional protective measures on their behalf.” a T-Mobile Spokesperson told BleepingComputer.

T-Mobile customers should remain vigilant on unsolicited text messages or emails pretending to be from T-Mobile.

Unfortunately, this is the last incident in order of time suffered by the company, below is the list of previous incidents:

  • In August 2021, a security breach impacted 54 million customers.
  • In February 2021, hundreds of users were hit with SIM swapping attacks.
  • In December 2020, T-Mobile disclosed a data breach that exposed customers’ network information (CPNI).
  • In March 2020, threat actors gained access to T-Mobile customers and employee personal info.
  • In 2019, T-Mobile disclosed data breach affecting prepaid wireless customers.
  • In 2018, data breach exposed personal information of up to 2 million customers.

Follow me on Twitter: @securityaffairs and Facebook

[adrotate banner=”9″][adrotate banner=”12″]

Pierluigi Paganini

(SecurityAffairs – hacking, data breach)

[adrotate banner=”5″]

[adrotate banner=”13″]


facebook linkedin twitter

Cybercrime data breach Hacking hacking news information security news IT Information Security Pierluigi Paganini Security Affairs Security News SIM swapping T-Mobile

you might also like

Pierluigi Paganini July 29, 2025
Seychelles Commercial Bank Reported Cybersecurity Incident
Read more
Pierluigi Paganini July 29, 2025
Microsoft uncovers macOS flaw allowing bypass TCC protections and exposing sensitive data
Read more

leave a comment

newsletter

Subscribe to my email list and stay
up-to-date!

    recent articles

    Seychelles Commercial Bank Reported Cybersecurity Incident

    Data Breach / July 29, 2025

    Microsoft uncovers macOS flaw allowing bypass TCC protections and exposing sensitive data

    Hacking / July 29, 2025

    U.S. CISA adds Cisco ISE and PaperCut NG/MF flaws to its Known Exploited Vulnerabilities catalog

    Security / July 28, 2025

    Critical WordPress Post SMTP plugin flaw exposes 200K+ sites to full takeover

    Security / July 28, 2025

    Scattered Spider targets VMware ESXi in using social engineering

    Cyber Crime / July 28, 2025

    To contact me write an email to:

    Pierluigi Paganini :
    pierluigi.paganini@securityaffairs.co

    LEARN MORE

    QUICK LINKS

    • Home
    • Cyber Crime
    • Cyber warfare
    • APT
    • Data Breach
    • Deep Web
    • Digital ID
    • Hacking
    • Hacktivism
    • Intelligence
    • Internet of Things
    • Laws and regulations
    • Malware
    • Mobile
    • Reports
    • Security
    • Social Networks
    • Terrorism
    • ICS-SCADA
    • POLICIES
    • Contact me

    Copyright@securityaffairs 2024

    We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept All”, you consent to the use of ALL the cookies. However, you may visit "Cookie Settings" to provide a controlled consent.
    Cookie SettingsAccept All
    Manage consent

    Privacy Overview

    This website uses cookies to improve your experience while you navigate through the website. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities...
    Necessary
    Always Enabled
    Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
    Non-necessary
    Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.
    SAVE & ACCEPT