AT&T ( T ) has been hit by a data breach impacting 73 million current and former account holders, including personal information such as Social Security numbers, the telecommunications company recently disclosed.

Following a release of customer data on the dark web two weeks ago, AT&T ( T ) launched an investigation and determined that the data was from 2019 or earlier and impacted 7.6 million current account holders and 65.4 million former account holders, AT&T ( T ) said. 

“The information varied by customer and account, but may have included full name, email address, mailing address, phone number, Social Security number, date of birth, AT&T ( T ) account number and passcode,” AT&T ( T ) said in a post on its website. 

The company added that if you were affected by the breach, AT&T ( T ) will reach out by mail or email and offer complimentary identity theft and credit monitoring services.

Concerned customers with any questions can also call AT&T ( T ) wireless customer service at 1-800-331-0500.

 How to update your AT&T ( T ) passcode 

If your account was impacted by the data breach, AT&T ( T ) has already reset your passcode. If you were not impacted by still want to do so, you can follow these steps:

 Go to your myAT&T Profile and sign in Scroll to "My linked accounts" and select it Select "Edit" for the passcode you want to update  Follow the steps to choose a new passcode 

Monitor your credit for free

In addition to resetting your passcode, AT&T ( T ) encourages customers to monitor their account activity and credit reports. 

“You can set up free fraud alerts from nationwide credit bureaus — Equifax ( EFX ), Experian ( EXPGF ), and TransUnion ( TRU ),” AT&T ( T ) said. “You can also request and review your free credit report at any time via Freecreditreport.com.”

Kiplinger experts also recommend seven smart moves to prevent identity theft, including securing your personal devices, safeguarding your Social Security number and using strong, diverse passwords.