Maui is a ransomware group that emerged in May 2021 with apparent financial motivations, though their limited known victim count suggests either highly selective targeting or a relatively small-scale operation. The group's origin and affiliations remain largely undocumented in public threat intelligence reporting, with no confirmed country of origin or clear links to other ransomware families established by major security agencies. Based on available information from security researchers, Maui operators appear to specifically target healthcare and public health sector organizations within the United States, though detailed attack methodology, initial access vectors, and encryption techniques have not been extensively documented in public CISA, FBI, or major security firm reporting. The group's limited public profile means that notable campaigns and high-profile victims beyond general healthcare targeting have not been widely reported or analyzed in mainstream threat intelligence sources. Current operational status of the Maui ransomware group remains unclear due to limited public documentation and intelligence reporting. The group has been linked to 1 public disclosures across our corpus. First observed on a leak site on May 1, 2021. The operation is currently inactive.
Sector and geography
This disclosure adds to ransomware activity in the Healthcare and Public Health sector, which has 54 disclosures indexed across all operators we track. Geographically, Unnamed medical facilities (12) is reported in United States, a country with 11,033 ransomware disclosures in our corpus.
If your organisation is affected
A listing by maui means Unnamed medical facilities (12) appeared on a ransomware extortion site and data attributed to it has been published. If this is your organisation, or a supplier you depend on, the priority is to confirm the intrusion and contain it before the window to act closes.
- Engage your incident-response team and preserve forensic evidence before remediating — do not wipe affected systems first.
- Force a password reset and revoke active sessions for exposed accounts; rotate any credentials, API keys or certificates that may have been in the stolen data.
- Assess regulatory notification duties (GDPR, NIS2, sector regulators) — many carry a 72-hour reporting clock from awareness.
- Report the incident to your national CERT, CISA (United States), as required for your jurisdiction.
- Monitor for the data appearing on maui's leak site and across paste and breach channels, and brief downstream partners who may be exposed through you.
How we know this. Darkfield monitors public ransomware leak sites continuously, archiving every new disclosure and the data later released against the victim. Each entry on this page is sourced from the operator's own publication and cross-checked against complementary OSINT feeds (RansomLook, ransomware.live, RansomWatch). We do not collect or host stolen data — only the metadata, timestamps and screenshots needed to make the public disclosure searchable and accountable. Records here are corrected when the original post is edited, retracted, or merged with another disclosure.
