Cyberattack affects 1.1 million CareFirst customers

""The information they got may or may not be useful directly, but it could help a bad guy get more clues about a person's identity," he said. "That could be useful to an adversary."

In many cases, data breaches can be larger than originally apparent, Forno added.

"As time goes on and the investigation continues, you never know if you'll find other leads that may change your initial assumptions," he said."