T-Mobile confirmed that recent reports of a new data breach are linked to notifications sent to a “very small number of customers” who fell victim to SIM swap attacks. “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,” a T-Mobile spokesperson told reporters “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.” T-Mobile refused to provide additional details when asked for more info on the total number of affected customers and the method used by the attackers to pull off the SIM swap attacks successfully. “We are not providing any additional information at this time. Thank you!” a company spokesperson told reporters. SIM swapping (also known as SIM hijacking) makes it possible for attackers to take control of a target’s mobile phone number by tricking or bribing the carrier’s employees to reassign the numbers to attacker-controlled SIM cards. This enables the threat actors to take control of their victims’ phone numbers and use them to bypass SMS-based multi-factor authentication (MFA), steal their credentials, log into the victims’ bank accounts to steal money, or hijack their online accounts by changing the passwords.
All T-Mobile customers be on the lookout for any suspicious text messages or emails pretending to be from T-Mobile. Don’t click any links if you receive one, as attackers could use them to harvest your credentials. It is also advised to enable multi-factor authentication whenever possible.