>>> AT&T IS INVESTIGATING A MASSIVE DATA BREACH AND HAS BEGUN NOTIFYING CURRENT AND FORMER CUSTOMERS WHO HAVE BEEN IMPACTED. >> YEAH, THE COMPANY CONFIRMS DATA HAS BEEN FOUND ON THE DARK WEB. THEY SAY 7.6 MILLION CURRENT ACCOUNT HOLDERS AND 65.4 MILLION FORMER ACCOUNT HOLDERS HAVE BEEN AFFECTED BY THIS. CBS NEWS SENIOR BUSINESS AND TECHNOLOGY CORRESPONDENT JO LING KENT IS FOLLOWING THE STORY FOR US. THAT IS HUNDREDS OF THOUSANDS OF PEOPLE WE ARE TALKING ABOUT, MANY MILLIONS OF PEOPLE HAD THEIR INFORMATION STOLEN. WHAT TYPE OF INFORMATION ARE WE TALKING ABOUT, JO LING? >> IT IS ALL THE USEFUL INFORMATION TO ACCESS YOUR CREDIT REPORTS AND YOUR FINANCIAL SITUATION. IT IS FULL NAMES, PHONE NUMBERS, SOCIAL SECURITY NUMBERS, YOUR AT&T ACCOUNT INFORMATION AND BEYOND. NOT EVERY SINGLE PERSON HAD EVERY PIECE OF PERSONAL INFORMATION STOLEN, BUT IT DEPENDS ON THE ACCOUNT. AT&T SAYS IT HAS LAUNCHED A ROBUST INVESTIGATION INTO WHY THIS HAPPENED. THEY SAID IT STARTED HAPPENING ABOUT TWO WEEKS AGO AND THEY DISCLOSED IT TO THE PUBLIC ON SATURDAY, BUT THEY DID NOT SAY WHY THIS HAPPENED OR WHO MIGHT BE RESPONSIBLE OR, IN MY VIEW, ONE OF THE MOST IMPORTANT DATA POINTS, WHY IT TOOK SO LONG TO FIGURE OUT THIS WAS HAPPENING, GIVEN THE FACT THAT DARK WEB HAS NOW OBTAINED FULL INFORMATION FROM PREVIOUS AND CURRENT CUSTOMERS. >> THAT IS SO RIGHT, JO LING. I WONDER IF THERE IS ANYTHING THAT CUSTOMERS OF AT&T CAN DO? HAVE THEY BEEN NOTIFIED? IF THEY WERE IMPACTED, ARE THERE ANY STEPS THEY CAN TAKE TO PROTECT THEMSELVES? >> AT&T SAYS THEY HAVE NOTIFIED AND REDONE PASSCODES FOR THOSE CURRENTLY IMPACTED. IF YOU WANT TO KNOW IF YOUR INFORMATION HAS BEEN LEVERAGED AGAINST YOU AND IF IT IS HURTING YOUR CREDIT, FOR EXAMPLE, THE BEST THING TO DO IS TO PULL YOUR CREDIT REPORT. LOOK AT THAT . IF YOU SEE ANY ACTIVITY THAT IS MALICIOUS, THAT IS NOT YOURS, THE BEST THING TO DO IS TO REPORT THAT. LOOK AT ALL THREE CREDIT BUREAUS. IF THERE ARE THINGS ON THERE THAT ARE NOT YOURS AND YOU ARE ABLE TO REPORT THAT AND PROCESS THAT, YOU ALSO WANT TO ASK TO HAVE YOUR CREDIT REPORT REVISED SO IT DOESN'T IMPACT WHEN YOU GO FOR A MORTGAGE, TRIED TO PURCHASE A VEHICLE OR ANYTHING WHERE YOUR CREDIT, YOU KNOW, MIGHT BE NECESSARY OR IMPACTED. THE OTHER THING TO DO, TOO, AFTER YOU GO THROUGH THAT PROCESS, FREEZE YOUR CREDIT AND UNFREEZE IT ONLY WHEN YOU NEED TO ACCESS IT. THAT IS A CRITICAL PIECE TO PROTECT YOURSELF. THERE HAVE BEEN SO MANY HACKS, AT&T AND 1 MILLION OTHERS, IT IS HIGHLY LIKELY YOUR INFORMATION IS ALREADY OUT THERE. >> FREEZING CREDIT IS A SMART MOVE. THE COMPANY, AT&T, HAS SAID TO PREVENT ANYTHING FURTHER, THEY HAVE RESET PASSCODES OF CURRENT USERS. WHAT ELSE DO WE KNOW ABOUT WHAT THEY ARE DOING NOW TO PROTECT THEIR DATA MOVING FORWARD? >> THEY SAY THEY HAVE A ROBUST INVESTIGATION GOING ON. THEY ARE TRYING TO FIGURE OUT HOW IT STARTED. AT&T, THEY HAVE HAD A REALLY ROUGH TIME WHEN IT COMES TO DATA AND OUTAGES. JUST A COUPLE MONTHS AGO, THERE WAS THAT WIDESPREAD OUTAGE AFFECTING MAJOR CITIES ACROSS THE COUNTRY WITH PEOPLE CANNOT ACCESS THEIR PHONES AND THEIR DATA. ABOUT A YEAR AGO, I BELIEVE, THERE WAS ANOTHER MAJOR DATA BREACH. AT&T HAS BEEN STRUGGLING. THIS IS CERTAINLY HURTING THE COMPANY. THE ISSUE HERE IS, IF IT IS REALLY A CONSUMER DRIVEN ENVIRONMENT, TRUST IS THE NUMBER ONE CHALLENGE. WHEN YOU THINK ABOUT COMPANIES, AT&T, THEY ARE CERTAINLY NOT DOING VERY WELL ON THAT TODAY. >> IT IS A VULNERABILITY IN OTHER COMPANIES, AS WELL.