If you pay a Georgia Power bill, check your mail and inbox. The utility said Monday that an "unauthorized third party" got into its online customer portal and saw limited account information. About 300,000 of its 2.8 million customers were affected, The Atlanta Journal-Constitution reported.

The total is about 400,000 accounts across Southern Co., the parent company. WBRC in Birmingham reported that roughly 100,000 of Alabama Power's 1.6 million accounts were affected.

The exposed details include names, addresses, phone numbers, email addresses and the last four digits of Social Security numbers. Southern Co. said no bank account numbers, payment card numbers or driver's license numbers were included.

"We recently detected suspicious activity involving our online customer portal," the company said. It said it stopped the activity, called law enforcement and found no evidence that the intruder still has access. The AJC reported the hack happened last week.

Georgia Power is notifying customers by email and by mail. Affected customers will get one year of free credit monitoring through Equifax, WBRC reported. The company has not said exactly which records each person lost or how the intruder got in.

The breach appears to involve customer accounts, not the systems that run the power grid, WSB-TV reported. Federal officials have warned that hackers, some tied to foreign governments, keep targeting utilities, water systems and other public services.

What to do now: Watch bank and card statements. Pull your free credit reports. Be wary of calls, texts or emails that claim to be from Georgia Power and ask for payment or passwords. Go straight to the utility's website or app instead of clicking links.

What we know: About 300,000 Georgia Power customers had limited account details exposed through the web portal.
What we don't: How the intruder got in and who is behind it.