Disclosure context

About Atomsilo

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. The group has been linked to 5 public disclosures across our corpus. First observed on a leak site on December 21, 2021; most recent post February 24, 2026. The operation is currently active.

Timeline of this disclosure

February 24, 2026A large bank in Asia listed by Atomsiloon the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Financial Services sector, which has 516 disclosures indexed across all operators we track.

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.

Ransomware victim disclosure

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A large bank in Asia

Claimed by Atomsilo · listed 3 months ago

Age

since listed · data leaked

Status timeline

Listed
Feb 24, 2026
Data leaked

At a glance

Group: Atomsilo
Status: Data leaked
Sector: Financial Services
Listed on leak site: Feb 24, 2026

About the victim

AI dossier — public-source company profile

The victim is described only as a large bank operating in Asia, offering diversified financial services including deposits, loans, and wealth management to individual and corporate clients. The institution purportedly operates across multiple countries in the Asia region with significant market share. No specific company name, domicile, or further identifying details are available from the leak post or public site.

Industry: Retail & Corporate Banking

Attack summary

Severity: medium — The disclosed status is 'data_published', suggesting some data release occurred, but the leak post is AI-generated boilerplate with no verifiable details, no data inventory, no proof count, and no confirmed regulated data exposure; confidence in actual impact is very low, preventing a higher severity classification.

Atomsilo claims to have attacked a large Asian bank and has published data ('data_published' status), though the leak post provides no specifics on whether encryption, exfiltration, or both occurred, and no data size or ransom demand is stated.

medium

Original description

AI-summarised, not from the leak post

A large bank in Asia refers to a financial institution that provides diversified services like deposits, loans, wealth management to individual and corporate clients. Being large-scale, they generally operate across several countries in the Asia region, often having a significant market share. This also involves operating digital banking services, given the widespread internet usage. Their influence in the finance sector can affect regional economic stability.

Sources

Victim sitebank.com
Leak posthttp://npmh5ahrgakbniuntyc7io4adm6ietbdbuejrfonowqtyqn24or556qd.onion/leaks.html/post.html?id=bank

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.