Disclosure context

About kairos

Kairos is a recently emerged ransomware group first observed in November 2024 that appears to be primarily financially motivated, having targeted approximately 75 victims across multiple sectors and countries. The group's origin and potential affiliations remain unclear due to limited public documentation from established threat intelligence sources, and it is unknown whether they operate as a Ransomware-as-a-Service model or as an independent entity. Based on available targeting data, Kairos appears to focus their operations primarily on English-speaking countries including the United States, Australia, United Kingdom, and Canada, with additional activity observed in Germany, while their sector targeting spans education, healthcare, agriculture and food production, and business services, though specific attack methodologies, initial access vectors, and encryption techniques have not been publicly documented by major security organizations. Given the group's recent emergence in late 2024, there are no widely reported notable campaigns or high-profile incidents documented by CISA, FBI, or established security research firms. As of current reporting, Kairos appears to remain active based on their recent first observation date, though comprehensive threat intelligence profiles from major security organizations have not yet been published due to the group's nascent operational timeline. The group has been linked to 86 public disclosures across our corpus. First observed on a leak site on November 13, 2024; most recent post May 15, 2026. The operation is currently active.

Timeline of this disclosure

May 11, 2026Arwini listed by kairoson the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Not Found sector, which has 4,859 disclosures indexed across all operators we track. Geographically, Arwini is reported in DE, a country with 333 ransomware disclosures in our corpus.

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.

Ransomware victim disclosure

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Arwini

Claimed by kairos · listed 9 days ago

Age

since listed · data leaked

Status timeline

Listed
May 11, 2026
Data leaked

At a glance

Group: kairos
Status: Data leaked
Country: DE
Sector: Not Found
Listed on leak site: May 11, 2026

About the victim

AI dossier — public-source company profile

Arbeitsgemeinschaft Wirtschaftlichkeitsprüfung Niedersachsen e.V. (ARWINI) is a registered association in Lower Saxony, Germany, operating within the statutory health insurance sector under SGB V. It serves as the joint audit and efficiency-review body bringing together the regional panel physicians' association (KVN) and statutory health insurers to oversee billing, care appropriateness, and efficiency of contractual outpatient medical services. Its work is administrative and regulatory in nature, handling formal procedures and consultations related to healthcare billing oversight.

Industry: Statutory Health Insurance Audit & Efficiency Review (Public Healthcare Administration)
Address: Lower Saxony, Germany

Attack summary

Severity: critical — ARWINI handles regulated healthcare and billing data pertaining to statutory health insurance under German SGB V, involving physician and patient-adjacent records. Data has been published, meaning confirmed exfiltration of sensitive regulated data in the healthcare/public administration domain, qualifying as critical under GDPR and sectoral health-data regulations.

The Kairos ransomware group claims to have attacked ARWINI and has published data (disclosed status: data_published), indicating exfiltration of data from the organisation. No specific ransom amount or data volume was stated in the post.

critical

Data the group says was taken

AI dossier — extracted from the leak post

Healthcare billing records
Physician audit and inspection data
Contractual outpatient care documentation
Statutory health insurer correspondence
Internal administrative procedures

What the group claims

Arbeitsgemeinschaft Wirtschaftlichkeitsprüfung Niedersachsen e.V. (ARWINI) is a registered association in Lower Saxony, Germany, whose public role is to host the joint Wirtschaftlichkeitsprüfung setup for statutory health insurance under SGB V. It brings together the KVN (the regional association of panel physicians) and the health insurers in a shared inspection / audit structure for contractual outpatient care. Day-to-day work covers procedures, consultations with physicians where relevant, and formal processes linked to efficiency and appropriateness of care and billing. The brand ARWINI is the short name used in official documents and online; arwini.de is the domain commonly associated with that name. Operationally the body sits in the social health sector rather than ordinary consumer or tech markets.

Source

Indexed 9 days ago

This page surfaces a public ransomware disclosure indexed by Darkfield. Original posts come from the operator's own leak site; we cross-check against ransomware.live, RansomLook and RansomWatch where applicable. Share this URL freely.