KillSec

KillSec is a ransomware threat actor and ransomware operation that evolved from an Anonymous-aligned hacktivist group into a financially motivated hybrid extortion actor and RaaS-style operation. The reporting describes KillSec as having transitioned from hacktivism to ransomware, and as offering affiliates additional capabilities including DDoS and data-stealer tooling. High-confidence references place KillSec among active ransomware groups in 2025–2026, including attacks against healthcare-sector businesses, a South Korean exhibition management platform, and healthcare institutions in Brazil. Comparative reporting cited KillSec as one of the most common ransomware strains affecting healthcare businesses in the first nine months of 2025, with 12 recorded attacks in that category. The content also notes that KillSec continued to list healthcare providers among its victims, unlike some groups that reportedly avoid that sector. No specific malware family technical details, infection chain, encryption routine, or indicators of compromise were provided in the source content.