- Marquis confirms that the August 2025 breach affected more than 670,000 people
- Attack linked to SonicWall MySonicWall brute force incident exposing firewall configurations
- Marquis is suing SonicWall, which questions the connection between the two events.
The August 2025 cyberattack on Marquis affected more than 670,000 people, the company confirmed earlier this week.
Marquis is an American financial technology company that creates software for banks and credit unions and, to defend its internal network, uses a firewall built by SonicWall.
In mid-September 2025, SonicWall warned its firewall customers to reset their passwords after anonymous threat actors broke into the company’s MySonicWall cloud service.
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Lawsuit filed
This tool allows SonicWall firewall users to back up their firewall configuration files, including network rules and access policies, VPN configurations, service credentials (LDAP, RADIUS, SNMP), or administrator usernames and passwords (if stored in the configuration).
SonicWall later confirmed that all of its customers were affected, and Marquis said it was among them.
There were initially no reports on the number of people affected. Marquis filed reports with several Attorney General’s Offices, claiming that different types of information were stolen in different states. “Personal information potentially involved for Maine residents includes names, addresses, telephone numbers, Social Security numbers, taxpayer identification numbers, financial account information without security or access codes, and dates of birth,” he said in his Maine filing.
Now, beepcomputer It says the company confirmed more than 670,000 victims.
“The incident was limited to Marquis systems and did not impact our customers’ systems,” the company told affected people, according to the post. “Our client reviewed the affected files on December 10, 2025 and then worked to validate and identify individuals whose information may have been affected by the incident, and our client worked as quickly as possible to obtain the individuals’ most recent mailing address information.”
Meanwhile, Marquis filed a lawsuit against SonicWall, alleging that the attack was a result of the company’s conduct. SonicWall, on the other hand, maintains that there is no evidence that the two incidents are related.
Through beepcomputer
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