montaury.com.br Listed by lockbit5 Ransomware Group: Ransomware Claim — What’s Alleged & What To Do
montaury.com.br was listed by the lockbit5 ransomware group on December 05, 2025 after internal files were exfiltrated in a ransomware attack; the actual date of the intrusion has not been established. Anyone who has interacted with the organisation should review their own records and monitor accounts for signs of misuse.
Ransomware operations continue to target professional services firms that hold sensitive client information, and listings on leak sites have become a standard element of extortion campaigns. On December 05, 2025, the group operating as lockbit5 added montaury.com.br to its leak site, stating that internal files had been taken from the Brazilian intellectual-property law firm Montaury Pimenta, Machado & Vieira de Mello.
The number of individuals affected and the precise volume of data remain undisclosed. No independent confirmation of the exfiltration or subsequent publication of files has been made public.
Breaking down the breach
The only confirmed public record is the December 05, 2025 listing on the lockbit5 site. The group claims to have exfiltrated internal files during a ransomware intrusion. No date of intrusion, duration of access, or quantity of data is stated in the available record. The number of people or clients potentially affected is listed as unknown.
Inside lockbit5
LockBit operates as a ransomware-as-a-service affiliate model in which developers supply encryption tools and a leak platform while separate operators conduct intrusions. Public reporting has documented the group’s repeated use of double-extortion tactics: data are encrypted on victim systems and copies are threatened with publication if ransom demands are not met. The group has appeared on leak sites since at least 2020 and has claimed victims across multiple sectors and countries.
In this instance the group claims montaury.com.br as a victim; that claim has not been corroborated by the organisation or by independent forensic reporting.
About montaury.com.br
Montaury Pimenta, Machado & Vieira de Mello is a Brazilian law firm specialising in intellectual-property matters. Such firms routinely receive, store and transmit patent applications, trademark filings, trade-secret documentation and correspondence with clients and foreign counsel. The confidentiality of this material is protected under Brazilian professional-secrecy rules and international IP treaties.
What was likely exposed
The published record states only that internal files were exfiltrated. No inventory of file types or client names has been released. Organisations of this type commonly hold client identifiers, case correspondence, technical descriptions of inventions and contractual documents; however, the exact contents of the material allegedly taken from montaury.com.br remain unconfirmed.
Why it matters
Intellectual-property filings can contain commercially sensitive technical information whose premature disclosure may affect patent validity or competitive position. Clients of the firm may face secondary risks if their identities or case details appear in any published material. For the firm itself, the incident raises questions about the handling of privileged communications and the adequacy of existing access controls.
What to do if you're exposed
Individuals or organisations that believe they may have been clients of the firm should monitor official communications from montaury.com.br and consider placing fraud alerts with credit bureaus where applicable. Passwords associated with any accounts linked to the firm should be changed, and multi-factor authentication should be enabled on remaining services.
- Review recent account statements and legal correspondence for anomalies.
- Request a copy of any personal data held by the firm under applicable Brazilian data-protection rules.
- Run a free exposure scan of your email address against known breach data sets to check for additional surface.
AICompiled with AI assistance from public sources and published under our editorial standards.
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Publicly posted by lockbit5 — unverified claim, pending independent verification
Breach listings — particularly those originating from ransomware or leak sites — are third-party claims that may be unverified, incomplete, or inaccurate. A listing does not by itself confirm that a breach occurred or that any specific data was exposed. Severity is an automated assessment, not a definitive rating. Verification status is shown where available.
Attributions to threat groups and methods reflect public reporting and, in some cases, unverified claims made by the groups themselves; they may be incomplete or later revised. Recent Breaches and GalaxyWarden are independent and are not affiliated with, and do not endorse, any company or group named on this page. This information is aggregated from public sources for awareness only and is not legal, security, or investment advice.