General Motors suffers credential stuffing attack

American car manufacturer General Motors (GM) says it experienced a credential stuffing attack last month. During the attack customer information and reward points were stolen.

The subject of the attack was an online platform, run by GM, to help owners of Chevrolet, Buick, GMC, and Cadillac vehicles to manage their bills, services, and redeem rewards points.

Credential stuffing

Credential stuffing is a special type of brute force attack where the attacker uses existing username and password combinations, usually ones that were stolen in a data breach on another service.

The intention of such an attack is not to take over the website or platform, but merely to get as many valid user account credentials and use that access to commit fraud, or sell the valid credentials to other criminals.

To stop a target from just blocking their IP address, an attacker will typically use rotating proxies. A rotating proxy is a proxy server that assigns a new IP address from the proxy pool for every connection.

The attack

GM disclosed that it detected the malicious login activity between April 11 and April 29, 2022, and confirmed that the threat actors exchanged customer reward bonuses of some customers for gift certificates.

The My GM Rewards program allows members to earn and redeem points toward buying or leasing a new GM vehicle, as well as for parts, accessories, paid Certified Service, and select OnStar and Connected Services plans.

GM says it immediately investigated the issue and notified affected customers of the issues.


GM contacted victims of the breach, advising them to follow instructions to recover their GM account. GM is also forcing affected users to reset their passwords before logging in to their accounts again. In the notification for affected customers, GM said it will be restoring rewards points for all customers affected by this breach.

GM specifically pointed out that the credentials used in the attack did not come from GM itself.

“Based on the investigation to date, there is no evidence that the log in information was obtained from GM itself. We believe that unauthorized parties gained access to customer login credentials that were previously compromised on other non-GM sites and then reused those credentials on the customer’s GM account.”

Stolen information

Attackers could have accessed the following Personally Identifiable Information (PII) of a compromised user:

  • First and last name
  • Email address
  • Physical address
  • Username and phone number for registered family members tied to the account
  • Last known and saved favorite location information
  • Search and destination information

Other information that was available was car mileage history, service history, emergency contacts, Wi-Fi hotspot settings (including passwords), and currently subscribed OnStar package (if applicable).

GM is offering credit monitoring for a year.


What could GM have done to prevent the attack? It doesn’t currently offer multi-factor authentication (MFA)which would have stopped the attackers from gaining access to the accounts. GM does ask customers to add a PIN for all purchases.

This incident demonstrates how dangerous it is to re-use your passwords for sites, services and platforms. Even if the account doesn’t seem that important to you, the information obtainable by accessing the account could very well be something you wish to keep private.

Always use a different password for every service you use, and consider using a password manager to store them all. You can read some more of our tips on passwords in our blog dedicated to World Password Day.

Stay safe, everyone!

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