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Service Employees International Union (SEIU)

listed as Service Employees' International Union · Claimed by Quantum · listed 4 years ago

51m
Age
since listed · data leaked

Status timeline

  1. ListedApr 12, 2022
  2. Data leakeddate unknown

At a glance

Group
Quantum
Status
Data leaked
Country
United States
Sector
Government
Listed on leak site
Apr 12, 2022

About the victim

AI dossier — public-source company profile

The Service Employees' International Union (SEIU) is a large North American labor union representing approximately 100,000 members across a broad range of public and social-service sectors. Its membership includes workers employed by school boards, hospitals, home care agencies, special care homes, retirement homes, emergency services, social services, and municipalities. The organization advocates for workers' rights and negotiates collective agreements on behalf of its members.

Industry
Labor Union & Worker Representation

Attack summary

Severity: high — Data has been published (confirmed exfiltration) and the union represents ~100,000 members across sensitive sectors including healthcare, emergency services, and social services, meaning PII at meaningful scale is likely exposed.

The Quantum ransomware group claims to have exfiltrated data from SEIU, with the disclosure status indicating data has been published. The affected data likely pertains to union members and organizational operations across public-sector and healthcare-adjacent workplaces.

high

Data the group says was taken

AI dossier — extracted from the leak post
  • Union member personal information
  • Employee/membership records
  • Organizational operational data
  • Collective agreement documents
  • Contact and payroll information

What the group claims

SEIU represents approximately 100,000 members. SEIU represents members who work for school boards, home care agencies, hospitals, special care homes, retirement homes, emergency services, social services, and municipalities, among many others

Source

Indexed 4 years 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.

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Disclosure context

About Quantum

Quantum is a ransomware group that emerged in September 2021, operating with primarily financial motivations and demonstrating a focus on high-value targets across English-speaking nations. The group's geographic targeting patterns and operational characteristics suggest possible connections to established ransomware ecosystems, though specific attribution or confirmed affiliations with other threat actors remain undocumented in public reporting. Quantum operators typically employ double extortion tactics, combining data encryption with the threat of public data exposure to maximize pressure on victims, and their campaigns have consistently targeted sectors with critical operational dependencies including business services, manufacturing, and information technology infrastructure. The group has maintained a relatively low public profile compared to other major ransomware operations, with their 68 documented victims representing a more selective approach to target acquisition rather than broad-scale campaigns. Despite limited public law enforcement reporting specifically focused on Quantum operations, the group's continued activity pattern suggests they remain an active threat as of recent observations, though comprehensive operational details remain scarce in publicly available threat intelligence reporting. The group has been linked to 68 public disclosures across our corpus. First observed on a leak site on September 9, 2021; most recent post December 9, 2022. The operation is currently inactive.

Also tracked as: QuantumLocker, Mount Locker, DagonLocker.

Timeline of this disclosure

  • April 12, 2022Service Employees' International Union listed by Quantumon the group's public leak site

Other recent disclosures by Quantum

Quantum has been linked to 68 public victims on Darkfield. A sample of the most recent:

See the full Quantum dossier →

Sector and geography

This disclosure adds to ransomware activity in the Government sector, which has 685 disclosures indexed across all operators we track. Geographically, Service Employees' International Union is reported in United States, a country with 11,033 ransomware disclosures in our corpus.

If your organisation is affected

A listing by Quantum means Service Employees' International Union 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 Quantum'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.