HOMETHREATSRyuk Stealer
APT / THREAT GROUP

Ryuk Stealer

3
aliases
Last seen:Mar 17, 2026

Intelligence Profile

Information Stealer that searches for sensitive documents and uploads its results to an FTP server. Skips files with known Ryuk extensions.

Threat Analysis

Ryuk Stealer is a known-sophistication threat actor of undetermined national origin, engaged in cyber operations with a primary motivation of unknown activity patterns.

External References

→https://analyst1.com/file-assets/Nationstate_ransomware_with_consecutive_endnotes.pdf
→https://twitter.com/VK_Intel/status/1171782155581689858
→https://www.bleepingcomputer.com/news/security/ryuk-related-malware-steals-confidential-military-financial-files/
→https://www.crowdstrike.com/blog/sidoh-wizard-spiders-mysterious-exfiltration-tool/

Quick Facts

TypeAPT / Threat Group
Aliases3

Also Known As

win.ryuk_stealerSidohRyuk Stealer

External Intelligence

Malpedia: win.ryuk_stealer

Research Links

MITRE ATT&CK VirusTotal Google (news) Twitter/X search
Data sourced from Malpedia, Ransomware.live, RansomLook, and CTIWATCH OSINT collection. Actor attribution is based on available intelligence and may be incomplete.
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Ryuk Stealer — APT / Threat Group | Threat Intelligence | CTIWATCH.COM