Western Alliance Bank says October cyber attack impacted 22,000 customers

Phoenix, Arizona-based Western Alliance Bank said the sensitive personal information of almost 22,000 individuals was compromised during a significant data security incident it suffered in October.

 

Headquartered in Phoenix, Western Alliance Bank provides tailored commercial banking solutions and consumer products in key markets nationwide. The bank is a subsidiary of Western Alliance Bancorporation which also runs Alliance Association Bank, Alliance Bank of Arizona, Bank of Nevada, AmeriHome Mortgage, and First Independent Bank.

 

In a data security incident notice filed with the Office of Maine Attorney General, Western Alliance Bank said that in October, an unauthorised third party exploited an unknown vulnerability in a third party file transfer application. This allowed the third party to gain access to a limited portion of the bank’s systems and exfiltrate stored data records.

 

The bank said it discovered the cyber security incident on January 27 and immediately launched an investigation, with assistance from external cyber security experts, to determine the scope of the incident.

“Our investigation determined that the unauthorised actor acquired certain files from the systems from October 12, 2024, to October 24, 2024,” reads the notice.

 

The compromised data included names, Social Security numbers, dates of birth, financial account numbers, driver’s license numbers, tax identification numbers, and passport details. Western Alliance said in its filing with the Maine state regulator that at least 21,899 individuals were impacted by the incident.

 

“Western Alliance has taken and will continue to take steps to reduce the risk of this type of incident occurring in the future, including enhancing our technical security measures,” the bank added.

 

While Western Alliance found no evidence of the compromise data being misused, it has advised all affected individuals to regularly monitor their credit reports, account and benefit statements and report any suspicious activity to law enforcement authorities, including the police and the state attorney general. 

 

The bank has also offered one year of complimentary identity protection and credit monitoring services through Experian IdentityWorks Credit 3B to all affected individuals.

 

The Clop ransomware recently claimed responsibility for the cyber attack on Western Alliance and listed it as a victim on its data leak site. The bank has not responded to the hacker group’s claims nor has it shared details on whether it paid a ransom to regain access to the stolen data.