US-based Flagstar Bank has suffered a data breach that has hit over 1.5 million customers.

The bank was hacked over two days in December, with the unidentified attackers lifting the name of each customer or other personal identifier in combination with their social security number.

“After an extensive forensic investigation and manual document review, we discovered on June 2, 2022 that certain impacted files containing your personal information were accessed and/or acquired from our network between December 3, 2021 and December 4, 2021,” the bank says in a breach incident notice to customers. “We have no evidence that any of the information has been misused. Nevertheless, out of an abundance of caution, we want to make you aware of the incident.”

The bank - which was also recently a victim of the Accellion corporate document heist - says it is offering all affected customers two years of free identity monitoring services from Kroll, including credit monitoring, fraud consultation, and identity theft restoration.