21,899 Bank Customers Affected As US Lender Suffers Cybersecurity Breach, Hacker Taps Social Security Numbers and Other Sensitive Information

A billion-dollar bank is warning customers after a cybersecurity breach affecting thousands of customers.

In a filing with the Office of the Maine Attorney General, Western Alliance Bank says an unauthorized actor exploited a vulnerability in a third-party file transfer software system it uses.

The breach, which was discovered in late January and happened in October, impacts 21,899 customers, according to the filing.

“Western Alliance learned that an unauthorized actor had potentially accessed some of Western Alliance’s data on January 27, 2025. Our investigation determined that the unauthorized actor acquired certain files from the systems from October 12, 2024, to October 24, 2024…

On February 21, 2025, we determined that the files contained some of your personal information, including your name and Social Security number. The files may have also contained your date of birth, financial account number, driver’s license number, tax identification number, and/or passport, if you provided it to Western Alliance.”

The bank says it has informed law enforcement about the data breach and is offering customers a 12-month complimentary membership to an identity-theft protection service.

Western Alliance Bank currently has approximately $81 billion in total assets, according to the Federal Reserve.

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