Disclosure context

About TEAM UNDERGROUND

TEAM UNDERGROUND is a ransomware group first observed in May 2026 with an apparent financial motivation, though its limited operational history makes comprehensive attribution difficult at this time. With only a single known victim recorded to date, the group has demonstrated a targeting preference for the Audit, Tax Advisory, and Legal Services sector, suggesting a deliberate focus on organizations that handle sensitive financial, legal, and confidential client data — a common strategic choice among financially motivated threat actors seeking high-value exfiltration leverage. Given the group's extremely recent emergence and minimal operational footprint, detailed technical indicators regarding their initial access vectors, tooling, encryption methodology, or affiliation with broader ransomware ecosystems have not yet been publicly documented by authoritative sources such as CISA, the FBI, Mandiant, or equivalent research bodies. No confirmed affiliations with known ransomware-as-a-service platforms or established threat actor groups have been publicly established, nor have any notable high-profile campaigns, law enforcement actions, or ransom figures been attributed to this group in open-source reporting. TEAM UNDERGROUND should currently be regarded as an emerging and closely monitored threat, with its full capabilities, infrastructure, and operational scope remaining largely uncharacterized pending further observed activity and independent security research. The group has been linked to 6 public disclosures across our corpus. First observed on a leak site on May 14, 2026; most recent post May 21, 2026. The operation is currently active.

Timeline of this disclosure

May 18, 2026TPA Group (.com) listed by TEAM UNDERGROUNDon the group's public leak site

Ransom demanded: $281 million

Sector and geography

This disclosure adds to ransomware activity in the Audit, Tax Advisory & Legal Services sector.

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

← All victims

TPA Group

listed as TPA Group (.com) · Claimed by TEAM UNDERGROUND · listed 3 days ago

$281 million

Ransom

demanded

Age

since listed · listed for ransom

Status timeline

Listed
May 18, 2026

Current state: Listed for ransom

At a glance

Group: TEAM UNDERGROUND
Status: Listed for ransom
Sector: Audit, Tax Advisory & Legal Services
Listed on leak site: May 18, 2026
Ransom demanded: $281 million

About the victim

AI dossier — public-source company profile

TPA Group is a Central and Eastern European professional services firm offering audit, legal, accounting, and tax advisory services. The group operates across 12 countries including Austria, Poland, Romania, Slovakia, Croatia, and others in the CEE/SEE region, with dozens of office locations. It is one of the leading tax and audit firms in Central and Eastern Europe.

Industry: Audit, Tax Advisory & Legal Services

Attack summary

Severity: high — TPA Group is a major professional services and tax advisory firm handling sensitive financial, legal, and audit data for corporate clients across 12 countries. A successful attack would expose highly sensitive client financial and legal records at significant scale. However, no exfiltration proof or data inventory has been published, preventing a 'critical' classification.

TEAM UNDERGROUND claims an attack on TPA Group's main entity (tpa-group.com) with a ransom demand of $281 million, and a separate claim against tpa-group.sk valued at $15 million; no details on encryption or exfiltration methods are provided in the post.

high

The leak post

captured from the group's site

All data | Underground store Data Announcements All data Afghanistan Albania Algeria American Samoa Andorra Angola Anguilla Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Brazil British Virgin Islands Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Colombia Comoros Congo Congo, Democratic Republic Cook Islands Costa Rica Côte d`Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic East Timor Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands Faroe Islands Fiji Finland France French Guiana French Polynesia Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guam Guatemala Guinea Guinea-Bissau Guyana Haiti Honduras Hong Kong Hungary Iceland India Indonesia Iran Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jordan Kazakhstan Kenya Kiribati Kuwait Kyrgyzstan Laos Latvia Lebanon Lesotho Liberia Libya Liechtenst…

Sources

Victim sitetpa-group.com
Leak posthttp://47glxkuxyayqrvugfumgsblrdagvrah7gttfscgzn56eyss5wg3uvmqd.onion

Source

Indexed 3 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.