Ransomware Gang Exposes Data of 672,000 Individuals in Massive Cyberattack

Post Views: 8

Marquis Discloses Ransomware Attack Resulting in Theft of Sensitive Data

A Texas-based financial services provider, Marquis, has disclosed that a ransomware attack in August 2025 resulted in the theft of sensitive data belonging to over 672,000 individuals. The attack also disrupted operations at 74 banks across the United States.

Services Provided by Marquis

Marquis provides digital marketing, data analytics, compliance, and CRM services to more than 700 banks, credit unions, and mortgage lenders in the US.

Details of the Attack

The company revealed that the ransomware gang compromised its network by exploiting a vulnerability in a SonicWall firewall on August 14, 2025.

The attackers stole a wide range of personal and financial information, including names, dates of birth, addresses, phone numbers, Social Security numbers, Taxpayer Identification Numbers, and financial account information without security or access codes.

The breach was limited to Marquis’ systems and did not affect its customers’ systems.

Notification and Investigation

Marquis notified the affected individuals this week, stating that its customer reviewed the affected files on December 10, 2025, and worked to validate and identify individuals whose information may have been affected.

The company also worked to obtain the most recent mailing address information for the affected individuals.

Link to SonicWall Breach

The ransomware attack has been linked to a security breach disclosed by SonicWall on September 17, 2025, which affected about 5% of its firewall customers using its cloud backup service.

A Mandiant investigation found evidence linking the incident to a state-sponsored threat actor.

Lawsuits and Consequences

Marquis has filed a lawsuit against SonicWall, accusing the cybersecurity company of gross negligence and misrepresentation, which allegedly led to the ransomware attack.

The lawsuit claims that SonicWall’s conduct resulted in damages, loss of customers, harm to Marquis’ business reputation, and substantial diminution in its enterprise value.

Marquis is also defending over 36 consumer class action lawsuits stemming from the August 2025 cyberattack and the resulting data breach.

The company is seeking monetary damages, indemnification, contribution for any judgments in the related class actions, attorneys’ fees, and equitable relief.

Importance of Cybersecurity

The incident highlights the importance of robust cybersecurity measures and the need for companies to prioritize the protection of sensitive data.

The use of outdated or vulnerable software can have severe consequences, as seen in this case, where a single vulnerability in a SonicWall firewall led to a massive data breach.