**Trisec** is a recently emerged ransomware group that first appeared in February 2024, operating with apparent financial motivations based on their targeting of business-critical sectors. The group has demonstrated a focused operational scope with only three documented victims to date, suggesting either a highly selective targeting approach or nascent operational capabilities.
The origin and affiliations of Trisec remain largely unknown, with limited public intelligence available from major threat research organizations. Based on their targeting pattern across Sweden, Ireland, and Italy, the group appears to operate independently rather than as part of a larger ransomware-as-a-service ecosystem, though definitive attribution data is not yet available.
Trisec's attack methodology and technical capabilities have not been extensively documented by established security researchers, though their sector targeting suggests they focus on organizations with critical business operations in healthcare, technology, and business services sectors. The group's specific initial access vectors, encryption methods, and whether they employ data exfiltration tactics prior to encryption have not been publicly detailed by major cybersecurity firms or government agencies.
No major high-profile campaigns or significant ransomware payments have been publicly attributed to Trisec by law enforcement agencies such as the FBI or CISA, likely due to the group's recent emergence and limited victim count. The group remains active as of current intelligence reporting, though their operational tempo appears limited compared to more established ransomware operations. The group has been linked to 3 public disclosures across our corpus. First observed on a leak site on February 16, 2024; most recent post February 19, 2024. The operation is currently inactive.
Sector and geography
This disclosure adds to ransomware activity in the Healthcare sector, which has 2,600 disclosures indexed across all operators we track. Geographically, ki.se is reported in Sweden, a country with 111 ransomware disclosures in our corpus.
If your organisation is affected
A listing by trisec means ki.se 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, CERT-SE (Sweden), as required for your jurisdiction.
- Monitor for the data appearing on trisec'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.
