Marquis Software Solutions sued SonicWall, Inc. claiming SonicWall was at fault for Marquis' August 2025 cybersecurity incident, according to legal documents reviewed by local media.

The lawsuit comes after the data breach exposed sensitive personal and financial information for more than 672,000 people, including Social Security numbers and bank account details. Marquis alleges that the breach impacted approximately 400,000 individuals directly.

Allegations Against SonicWall

According to legal filings, Marquis claims that the threat actor used credentials stolen in a previous SonicWall incident to bypass Marquis' firewall, resulting in Marquis' incident. The company alleges that a security flaw in SonicWall's systems may have allowed attackers to steal critical configuration files that provided a roadmap into Marquis' network.

Marquis Software Solutions filed claims for:

• Negligence
• Unjust enrichment
• Negligent misrepresentation
• Contribution and indemnity

What Is Marquis Software Solutions?

Marquis, a fintech company based in Texas, provides data analytics tools to hundreds of banks. The company helps financial institutions study customer behavior and improve services, which means Marquis has access to highly sensitive financial and personal data.

The August 2025 ransomware attack affected customers across multiple regions, with more than half of the impacted individuals in Texas. The stolen data reportedly includes:

• Names
• Dates of birth
• Home addresses
• Bank account details
• Debit and credit card numbers
• Social Security numbers

According to reports from CyberGuy, the combination of this data is enough to commit serious identity fraud and could allow criminals to drain accounts, open loans, or impersonate victims.

Broader Context

This lawsuit adds to a growing trend of companies seeking accountability from third-party vendors following data breaches. The incident highlights the risks associated with supply chain security and the importance of proper firewall configuration and maintenance.

Cybersecurity experts note that ransomware remains one of the most persistent and costly threats, with average ransom demands rising to $1.3 million in 2025. Most breaches stem from familiar issues such as unpatched vulnerabilities, weak or reused passwords, lack of multi-factor authentication, and excessive user permissions.

What Happens Next

The lawsuit has not yet been filed in court, and SonicWall has not issued a public statement regarding the allegations. Marquis is seeking contribution and indemnity, which could mean significant financial liability for SonicWall if the claims are successful.

Legal proceedings in cases like this typically take months or years to resolve, and the outcome could set important precedents for how companies handle third-party security failures.

"Strong preventive measures such as patching, multi-factor authentication, proper configuration, and well-resourced security teams remain the most effective way to reduce the risk and impact of attacks," according to cybersecurity reports.

Individuals who believe they were affected by the data breach should contact Marquis Software Solutions directly for more information. The company has been working with affected parties since the breach was discovered.

Coverage Area

This story impacts residents across West Michigan and beyond, as Marquis serves financial institutions nationwide including banks in Michigan, Ohio, Indiana, and other Midwestern states. Michigan residents who hold accounts at banks using Marquis services may be among the 672,000 affected individuals.

Sources

• https://www.mondaq.com/unitedstates/new-technology/1765884/right-to-know-march-2026-vol-39
• https://www.foxnews.com/tech/banking-tech-data-breach-exposes-672k-ransomware-attack
• https://cyberguy.com/privacy/banking-tech-data-breach-exposes-672k-ransomware-attack/