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 19, 2026TPA Group SK listed by TEAM UNDERGROUNDon the group's public leak site

Ransom demanded: $15 million

Sector and geography

This disclosure adds to ransomware activity in the Consulting sector. Geographically, TPA Group SK is reported in Slovakia, a country with 3 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

← All victims

TPA Slovensko

listed as TPA Group SK · Claimed by TEAM UNDERGROUND · listed 2 days ago

$15 million

Ransom

demanded

Age

since listed · listed for ransom

Status timeline

Listed
May 19, 2026

Current state: Listed for ransom

At a glance

Group: TEAM UNDERGROUND
Status: Listed for ransom
Country: Slovakia
Sector: Consulting
Listed on leak site: May 19, 2026
Ransom demanded: $15 million

About the victim

AI dossier — public-source company profile

TPA Slovensko (tpa-group.sk) is the Slovak member firm of TPA Group, an international tax and accounting advisory network affiliated with Baker Tilly International. The firm provides tax, audit, and advisory services in Slovakia, offering tools such as a multi-country tax comparison platform (Tax-checker.com).

Industry: Tax & Accounting Advisory

Attack summary

Severity: medium — The post is a listing-level disclosure with a significant ransom demand ($15 million for the Slovak entity alone) against a professional tax and accounting firm, which would hold sensitive financial and client data. However, no proof files, data volume, or confirmed exfiltration details are provided, limiting severity to medium.

TEAM UNDERGROUND claims to have targeted both the international TPA Group entity (tpa-group.com, valued at $281 million ransom) and TPA Slovensko (tpa-group.sk, valued at $15 million ransom); the post implies data exfiltration or encryption but provides no explicit description of data stolen or proof files.

medium

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.sk
Leak posthttp://47glxkuxyayqrvugfumgsblrdagvrah7gttfscgzn56eyss5wg3uvmqd.onion

Source

Indexed 2 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.