killsec is a relatively new ransomware group that emerged in March 2024, operating with apparent financial motivations and demonstrating broad targeting across multiple geographic regions and industry sectors. The group's origin and potential state affiliations remain unclear due to limited public documentation from major threat intelligence sources, though their targeting pattern suggests opportunistic rather than geopolitically motivated operations. With 276 documented victims primarily concentrated in the United States, India, the United Kingdom, Brazil, and Belgium, killsec appears to focus heavily on healthcare, technology, business services, and financial sectors, indicating either specific tooling designed for these environments or opportunistic targeting of organizations with valuable data and high pressure to restore operations quickly. Given the group's recent emergence and the lack of detailed technical analysis from established cybersecurity firms like Mandiant or law enforcement advisories from CISA or FBI, specific details about their attack methodology, initial access vectors, encryption techniques, and extortion tactics have not been publicly documented in authoritative sources. The group remains active as of current reporting, though the limited intelligence profile suggests they may be either a smaller operation or one that has not yet attracted significant attention from major threat intelligence organizations despite their substantial victim count. The group has been linked to 284 public disclosures across our corpus. First observed on a leak site on March 21, 2024; most recent post July 23, 2026. The operation is currently active.
Sector and geography
This disclosure adds to ransomware activity in the Financial Services sector, which has 1,192 disclosures indexed across all operators we track. Geographically, csinsurance.mx is reported in Mexico, a country with 70 ransomware disclosures in our corpus.
If your organisation is affected
A listing by killsec means csinsurance.mx 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-MX (Mexico), as required for your jurisdiction.
- Monitor for the data appearing on killsec'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.
