Texas-based financial services provider Marquis Software Solutions told customers that its August 2025 ransomware incident—impacting Marquis systems used by dozens of U.S. banks and credit unions—was enabled by a prior compromise of SonicWall’s cloud services. Marquis said its third-party investigation concluded attackers obtained sensitive firewall information from SonicWall and used it to circumvent Marquis’ firewall, leading to theft of customers’ personal and financial data.
Marquis stated it had stored a backup of its firewall configuration in SonicWall’s cloud, and that the stolen configuration/backup data provided the credentials or details needed to facilitate the intrusion. SonicWall had publicly disclosed unauthorized access to its MySonicWall online customer portal / cloud backup service and initially reported that fewer than 5% of customers were affected, later updating that the exposure was broader (including firewall configuration data and related credentials/tokens). Marquis said it is evaluating options with its firewall provider, including seeking recoupment/compensation for incident-response costs incurred by Marquis and its customers.

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On January 29, 2026, reports said Marquis had started notifying hundreds of thousands of affected individuals and was considering seeking recovery of incident-response costs from SonicWall. SonicWall disputed that any connection between its September 2025 breach and Marquis' ransomware incident had been established.
By January 2026, Marquis informed customers that a third-party investigation concluded attackers likely used firewall configuration data stolen from SonicWall's cloud backup service to bypass Marquis' firewall. Marquis said the investigation ruled out an unpatched SonicWall flaw as the likely intrusion path.
In October 2025, SonicWall updated its earlier disclosure and said all customers using its cloud backup service were affected. The company clarified that firewall configuration data and credentials had been accessed.
Around the same period, Huntress reported a campaign that compromised more than 100 SonicWall SSLVPN accounts using stolen valid credentials. Huntress said it found no evidence tying those compromises to the cloud-backup breach.
In late September 2025, separate attacks attributed to the Akira ransomware gang targeted MFA-protected SonicWall VPN accounts. SonicWall said these attacks were unrelated to the MySonicWall cloud backup breach.
Following investigation of the MySonicWall incident, SonicWall said a Mandiant investigation found evidence connecting the portal breach to state-sponsored hackers. SonicWall also warned that stolen credentials or tokens could make it significantly easier to compromise affected customers' firewalls.
In September 2025, SonicWall disclosed unauthorized access to its MySonicWall customer portal affecting users of its cloud backup service. The company initially said about 5% of cloud-backup users were impacted.
In August 2025, Marquis Software Solutions experienced a ransomware incident that impacted dozens of U.S. banks and credit unions. Attackers stole customer personal and financial data, including Social Security numbers.
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