Marquis, a financial services company located in Texas, announced that a ransomware group accessed the personal information of over 670,000 people in a cyberattack in August 2025. This attack also caused problems for 74 banks across the country.

This company offers services like online marketing, data analysis, compliance assistance, and customer relationship management to more than 700 banks, credit unions, and mortgage companies nationwide.

Marquis reported in early December that they were hit by a ransomware attack on August 14, 2025, after the attackers gained access through a compromised SonicWall firewall. This information was included in data breach notifications submitted to U.S. Attorney General offices.

After getting into the network, the cybercriminals stole a variety of sensitive details, like names, birthdates, addresses, phone numbers, Social Security numbers, Taxpayer Identification Numbers, and unprotected financial account data.

According to the fintech firm, “The incident was confined to Marquis’s systems and did not affect our customers’ systems,” as stated in letters sent to the 672,075 individuals affected.

“Our customer examined the compromised files on December 10, 2025, and then worked to verify and identify the people whose data might have been impacted by the event, and they worked as quickly as possible to obtain the most current mailing addresses for those individuals.”

In January, Marquis attributed the ransomware attack to a security vulnerability SonicWall revealed on September 17, advising users to change their MySonicWall account passwords.

SonicWall stated at the time that approximately 5% of their firewall clients who used their cloud backup service were impacted by the event, and they warned that the attackers might obtain access credentials and tokens, making it “much easier” to compromise the firewalls of affected clients.

A Mandiant investigation into the September attack also found evidence that suggested the incident involved a government-backed hacking organization.

In February, Marquis sued SonicWall, alleging gross negligence and misrepresentation by the cybersecurity firm, which they claim led to the ransomware attack on their systems in August 2025.

“Marquis has suffered, and is still suffering, damages as a result of SonicWall’s actions, including a loss of customers, harm to its business reputation, lost business opportunities, revenue, and profit, as well as a large reduction in its enterprise value,” Marquis stated in the complaint.

The company also mentioned that it was defending itself against over 36 consumer class action lawsuits related to the August 2025 cyberattack and the following data breach. It was seeking financial compensation, protection against losses, contributions towards any judgments in these class actions, legal fees, and equitable relief.