A Uzzo Listed by sinobi Ransomware Group: Ransomware Claim — What’s Alleged & What To Do

On December 16, 2025, the ransomware group sinobi listed A Uzzo on its leak site. The listing states that internal files were exfiltrated from the firm during a ransomware attack. No further details on the volume of data, the number of individuals affected, or the timeline of the intrusion have been made public. This incident occurs amid a sustained pattern of ransomware operations targeting professional service firms that maintain records of financial and personal information. Such listings on leak sites are used by threat actors to apply pressure, regardless of whether the underlying claims are independently verified.

Breaking down the breach

The only confirmed public information is the December 16, 2025 listing by sinobi and the assertion that internal files were taken. The number of people affected remains unknown. No information has been released about the method of initial access, the duration of unauthorized activity, or whether any data was subsequently published or sold.

Who is sinobi?

Sinobi is a ransomware group that maintains a leak site where it lists organizations it claims to have compromised. Groups of this type commonly combine data exfiltration with encryption of systems, then use the public listing of victims to encourage payment. Their operations follow patterns seen across multiple ransomware actors that have been active in recent years, though specific claims made about any single victim require independent confirmation.

Who is A Uzzo?

A. Uzzo & Company is a certified public accounting firm based in Purchase, New York. It provides tax planning and preparation, estate and wealth advisory, and accounting consulting services to individuals, small businesses, and corporations. Firms in this sector routinely process detailed financial records, tax returns, and client correspondence that can span multiple years.

The information in question

The listing refers only to “internal files exfiltrated in ransomware attack.” The precise categories of data contained in those files have not been disclosed. Accounting firms of this type typically hold client tax documents, financial statements, payroll records, and communications that include identifying information, though the exact contents of the exfiltrated material remain unconfirmed.

What's at stake

Exposure of internal accounting files can create downstream risks for the firm’s clients, including potential misuse of financial details or identity information. For the organization itself, the incident may involve costs related to investigation, notification, and remediation, as well as reputational effects within its client base. The absence of Reported Details limits the ability to assess the full scope at this stage.

If your data was in this claimed breach

Individuals who are clients of A Uzzo or similar firms can take the following initial steps:

• Review recent account statements and tax filings for unexpected activity.
• Enable multi-factor authentication on financial and email accounts.
• Request a copy of any data the firm holds about them to understand what records exist.
• Run a free exposure scan of their email address against known breach data to check for prior appearances.

Further updates from the firm or official notifications should be monitored for any additional confirmed information.

AICompiled with AI assistance from public sources and published under our editorial standards.