Atomsilo is a ransomware operator currently active on public leak sites. Darkfield has indexed 5 public victims claimed by this operator between December 21, 2021 and February 24, 2026. Atomsilo is a relatively obscure ransomware group that emerged in December 2021, operating with financial motivations and maintaining a low profile compared to major ransomware operations. The group's origin and potential affiliations remain largely undocumented by major threat intelligence sources, though their limited scope of operations suggests they function as an independent entity rather than a large-scale Ransomware-as-a-Service operation. Based on available victim data, Atomsilo appears to employ targeted attacks against specific sectors, though their exact initial access vectors and technical methodologies have not been extensively documented by major security research organizations. The group has demonstrated a preference for targeting healthcare and financial services sectors, with documented activity primarily affecting organizations in Brazil and Japan, suggesting either regional focus or specific linguistic/cultural targeting capabilities. Atomsilo remains a minor player in the ransomware landscape with only five publicly documented victims, and their current operational status is unclear due to limited public reporting and analysis from major threat intelligence sources.

Recent disclosures by Atomsilo

All 5 indexed disclosures. Click any row for the full per-victim dossier.

• A large bank in AsiaFinancial Services · February 24, 2026
• Tegra VendasNot Found · Brazil · December 21, 2021
• Eisai Co., LtdHealthcare · Japan · December 21, 2021
• LIGHT CONVERSIONDecember 21, 2021
• Cristália - Indústria FarmacêuticaHealthcare · Brazil · December 21, 2021

See every disclosure indexed for Atomsilo →