Redstone Federal Credit Union today released an update for customers who were recently impacted by fraudulent Walmart.com charges.

“Redstone Federal Credit Union’s systems were not hacked or breached,” the release reads.

“Instead, Walmart.com was used to push through fraudulent charges. Upon discovering the fraudulent charges on member accounts, we have taken the necessary time to understand the situation, ensuring that all member information and funds remain secure.”

The fraudulent charges are part of a Bank Identification Number (BIN) attack, according to the release.

Redstone defined a BIN attack as “a type of fraud perpetrated by cybercriminals who attempt to access credit and debit card systems using a method that involves randomly guessing numerous combinations of card numbers until the correct information works, allowing for unauthorized charges.”

“No financial institution is immune to this type of attack,” the release says.

“Large retailers are particularly vulnerable to BIN attacks because they process a vast number of transactions daily, providing attackers with a wealth of data to exploit.”

Redstone Federal Credit Union currently operates 27 branch locations in north Alabama, according to its website.

It is one of the state’s largest credit unions.

“While it’s impossible to prevent fraudsters from using brute force techniques to guess card numbers, Redstone is glad to provide tools members can use to monitor and protect their account,” the release continues.

“These tools include account alerts and Redstone’s Card Control feature, both available through our mobile app and online.”

All fraudulent charges will be reversed either by Walmart.com or reimbursed by Redstone, according to the release.

And Walmart.com has already automatically refunded more than 77% of the fraudulent charges when they saw an increase in transactions, it adds.

“No Redstone member will suffer a loss as a result of this attack,” the release says.

“Redstone recognizes how frustrating fraudulent transactions can be, and we take this issue very seriously.”

“We have safeguards in place to help prevent fraudulent attacks on our members’ accounts and are diligent in our account monitoring,” it continues.

“We are in constant communication with VISA and other strategic partners to combat this situation that is affecting financial institutions nationwide.”

Redstone advised customers who notice any unauthorized charges on their account to contact their Fraud Department at 800-234-1234.

For more information about BIN attacks, customers can visit Redstone’s website.