Michigan-based Flagstar Bank, which has more than 150 branches across several US states, has disclosed a data breach that involved threat actors accessing files containing the personal information of 1.5 million individuals.
According to a data breach notification posted on Flagstar’s website and information provided by the company to authorities, the breach occurred in early December 2021. An investigation finalized on June 2 showed that the attackers had accessed files storing personal information.
It seems that different types of data were compromised for different customers, but the attacker appears to have obtained the social security numbers of at least some people. Affected individuals are being notified through snail mail.
The company said it does not have evidence that the compromised information has been misused, but it has decided to provide affected individuals two years of free identity monitoring services.
It’s unclear if the attack involved ransomware or any other type of malware. SecurityWeek has reached out to Flagstar for clarifications and will update this article if the company responds.
This is not the first time Flagstar has been targeted by cybercriminals. In March 2021, the bank started informing customers that it was one of the many companies affected by a hack involving a file transfer service from Accellion.
The Accellion service was compromised in late 2020, allowing cybercriminals to access the files of tens of organizations that had been using the service. In March 2021, the Cl0p ransomware gang published data stolen from Flagstar on its leak website.
The Accellion incident also impacted nearly 1.5 million Flagstar customers and the financial institution ended up reaching a $5.9 million deal to end litigation.
Related: Morgan Stanley Hit by Accellion Hack Through Third-Party Vendor
Related: Accellion Reaches $8.1 Million Settlement Over FTA Data Breach
Related: P&N Bank Data Breach Exposes Trove of User Data

Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.
More from Eduard Kovacs
- Vulnerabilities in Honda eCommerce Platform Exposed Customer, Dealer Data
- Barracuda Urges Customers to Replace Hacked Email Security Appliances
- Google Patches Third Chrome Zero-Day of 2023
- ChatGPT Hallucinations Can Be Exploited to Distribute Malicious Code Packages
- AntChain, Intel Create New Privacy-Preserving Computing Platform for AI Training
- Several Major Organizations Confirm Being Impacted by MOVEit Attack
- Verizon 2023 DBIR: Human Error Involved in Many Breaches, Ransomware Cost Surges
- Ransomware Group Used MOVEit Exploit to Steal Data From Dozens of Organizations
Latest News
- Consolidate Vendors and Products for Better Security
- Pharmaceutical Giant Eisai Takes Systems Offline Following Ransomware Attack
- Vulnerabilities in Honda eCommerce Platform Exposed Customer, Dealer Data
- North Korean Hackers Blamed for $35 Million Atomic Wallet Crypto Theft
- Cisco Patches Critical Vulnerability in Enterprise Collaboration Solutions
- Barracuda Urges Customers to Replace Hacked Email Security Appliances
- Android’s June 2023 Security Update Patches Exploited Arm GPU Vulnerability
- BBC, British Airways, Novia Scotia Among First Big-Name Victims in Global Supply-Chain Hack
