Was sesi.org.br hit by ransomware?

sesi.org.br was listed by the lockbit5 ransomware operation (Brazil), and stolen data was published on the group's leak site. Darkfield tracks this disclosure with the original leak post, screenshot and group context.

Who is the lockbit5 ransomware group?

lockbit5 is a ransomware operator tracked by Darkfield. See the full operator dossier for its known victims, sectors targeted, IOCs and leak-site infrastructure.

What data was leaked in the sesi.org.br breach?

lockbit5 published data attributed to sesi.org.br. Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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SESI - Serviço Social da Indústria

listed as sesi.org.br · Claimed by Lockbit5 · listed 3 months ago

Age

since listed · data leaked

Status timeline

ListedMar 30, 2026
Data leakeddate unknown

At a glance

Group: Lockbit5
Status: Data leaked
Country: Brazil
Sector: Education
Listed on leak site: Mar 30, 2026

About the victim

AI dossier — public-source company profile

SESI (Serviço Social da Indústria) is a Brazilian para-governmental organization managed by the National Confederation of Industry (CNI) that provides quality education, health, culture, and leisure services to industrial workers and their families across Brazil. It operates thousands of units nationwide, offering programs ranging from basic and adult education (EJA) to healthcare clinics and sports facilities. SESI is part of the 'Sistema Indústria' alongside SENAI, CNI, and IEL.

Industry: Education, Health & Social Services (Industrial Workers)
Address: Setor Bancário Norte, Quadra 1, Bloco C, Ed. Roberto Simonsen, Brasília, DF, Brazil
Employees: 10000+
Founded: 1946

Attack summary

Severity: critical — SESI serves millions of industrial workers and their families across Brazil, holding regulated PII, health records, and educational records at large scale. Data publication confirmed by 'data_published' status, involving a major national social services institution with sensitive personal and medical data.

LockBit 5 claims to have attacked SESI and published data (disclosed status: data_published), suggesting exfiltration of organizational data; no ransom amount was stated and specific data volume was not disclosed in the post.

critical

Data the group says was taken

AI dossier — extracted from the leak post

Employee personal records
Student/beneficiary records
Health service records
Administrative documents
Internal organizational data

What the group claims

SESI provides quality education, health, and cultural services aimed at improving the quality of lif...

Sources

Victim sitesesi.org.br
Leak posthttp://lockbitapt67g6rwzjbcxnww5efpg4qok6vpfeth7wx3okj52ks4wtad.onion/post/7060431d197d7ab73d607463c43fb45e

Source

Indexed 3 months 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 lockbit5

Based on the provided data, LockBit5 appears to be a recently emerged ransomware operation first observed in December 2025, representing what may be a new iteration or rebrand within the LockBit ransomware ecosystem, with primary financial motivations evidenced by their targeting of high-value sectors. Given the LockBit naming convention and the timing of emergence, this group likely operates from Eastern Europe or Russia and may represent either a continuation of previous LockBit operations or a new affiliate group leveraging the established LockBit brand, though specific organizational details remain undocumented by major security agencies. While detailed attack methodologies have not been publicly documented by CISA, FBI, or major security researchers, the group's targeting pattern across 157 victims suggests a broad-spectrum approach focusing on technology, manufacturing, healthcare, and transportation sectors primarily in the United States, Brazil, Germany, Italy, and Mexico. Due to the group's recent emergence in December 2025, there are no publicly documented notable campaigns or major incidents reported by established threat intelligence sources, though the victim count indicates active operations. The group appears to be currently active based on the recent first observation date, though comprehensive analysis from major security agencies has not yet been published given the short timeframe since emergence. The group has been linked to 278 public disclosures across our corpus. First observed on a leak site on December 7, 2025; most recent post June 11, 2026. The operation is currently active.

Timeline of this disclosure

March 30, 2026sesi.org.br listed by lockbit5on the group's public leak site

Other recent disclosures by lockbit5

lockbit5 has been linked to 278 public victims on Darkfield. A sample of the most recent:

See the full lockbit5 dossier →

Sector and geography

This disclosure adds to ransomware activity in the Education sector, which has 694 disclosures indexed across all operators we track. Geographically, sesi.org.br is reported in Brazil, a country with 319 ransomware disclosures in our corpus.

If your organisation is affected

A listing by lockbit5 means sesi.org.br 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.
Monitor for the data appearing on lockbit5'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.