SonicWall is urging customers to reset credentials after their firewall configuration backup files were exposed in a security breach impacting MySonicWall accounts. The company said it recently detected suspicious activity targeting the cloud backup service for firewalls, and that unknown threat actors accessed backup firewall preference files stored in the cloud for less than 5% of its customers. "Rather this was a series of brute-force attacks aimed at gaining access to the preference files stored in backup for potential further use by threat actors," it noted. The new preferences file includes the following changes -Randomized password for all local usersReset TOTP binding, if enabledRandomized IPSec VPN keys"The modified preferences file provided by SonicWall was created from the latest preferences file found in cloud storage," it said. "If the latest preferences file does not represent your desired settings, please do not use the file."