The cell phone numbers of nearly every AT&T customer were exposed in a massive breach of the telecommunications giant. The company made the announcement Friday. So, I’ve been talking with spokespeople for AT&T as the FBI regarding the risk to consumers.

The following were compromised:
• Nearly all the cell numbers of AT&T customers May 1 – Oct. 31, 2022.
• The numbers of customers of wireless providers that used AT&T’s network during that period.
• Phone logs of everyone those customers texted or called.
• What AT&T calls a “very small number” of customers who made calls or sent text messages Jan. 2, 2023.

And while AT&T says the contents of your phone calls or text messages were not exposed, an expert told NBC News that this kind of metadata can pose a huge national security risk.

There are many publicly available tools that thieves can use to connect names and phone numbers.  And with your metadata, it’s easy to develop a picture of your routine — where you work, who you talk to most often, where you sleep every night.
           
In an email to me Friday afternoon, the FBI acknowledged the potential national security threat writing in part, “In assessing the nature of the breach, all parties discussed a potential delay to public reporting under Item 1.05(c) of the SEC Rule, due to potential risks to national security and/or public safety.”

An AT&T spokesperson emailed me, confirming that the company started notifying affected customers by text and email Friday morning.  The spokesman has the following advice:

• Only open text messages or emails from those you know and trust.
• Never give personal information by text or email to someone you don’t know.
• Never click on a link in a text or email from an unknown sender even if you recognize a business name or logo. Instead, go directly to the company’s website.

The breach of AT&T’s call logs happened in April, just a month after another AT&T breach in which customer social security numbers were among the pieces of personal information stolen. Analysts who spoke with NBC News fear that thieves can combine information stolen in this breach with other breaches to try to steal your identity.

You may want to consider freezing your credit with all three agencies, Experian, Equifax and Transunion.  It’s now free and can be done as often as you like.  Some folks worry about the hassle of doing it because it requires you to thaw your credit before you can open a new account. But now federal law mandates that if you thaw your credit online or by phone, the bureaus must do it within an hour.  You can freeze your credit online.