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MITRE ATT&CK® Malware

S0446: Ryuk

Ryuk is a ransomware designed to target enterprise environments that has been used in attacks since at least 2018. Ryuk shares code similarities with Hermes ransomware.[1][2][3]

EnterpriseS0446MalwareObject v1.4Modified
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Glexia's Take · Automated analysis

Security context for executives and security teams

Automation confidenceMedium

S0446: Ryuk describes [Ryuk](https://attack.mitre.org/software/S0446) is a ransomware designed to target enterprise environments that has been used in attacks since at least 2018. [Ryuk](https://attack.mitre.org/software/S0446) shares code similarities with Hermes ransomware.(Citation: CrowdStrike Ryuk January 2019)(Citation: FireEye Ryuk and Trickbot January 2019)(Citation: FireEye FIN6 Apr 2019)

Executive priority

S0446: Ryuk is an official MITRE ATT&CK software. Glexia treats it as defensive behavior context for prioritizing monitoring, control validation, and response planning without using the object by itself as an attribution claim.

Technical view

Security teams should validate S0446: Ryuk by reviewing the official ATT&CK relationships, mapped tactics (the mapped ATT&CK tactic context), supported platforms (Windows), and available local telemetry before making detection or mitigation decisions.

Likely telemetry

  • Official ATT&CK relationships and object metadata
  • Network, endpoint, and security-tool telemetry

Detection direction

  • Validate whether S0446: Ryuk appears in your detection coverage and tabletop scenarios.
  • Use the object to align executive risk language with SOC, incident response, and detection engineering work.
  • Do not treat ATT&CK relationship context as attribution without corroborating evidence.

Mitigation priorities

  • Map the object to existing controls and identify missing telemetry or response ownership.
  • Prioritize mitigations that reduce exposure on the listed platforms and tactics.
  • Review adjacent ATT&CK relationships before changing policy, detections, or reporting language.
Additional notes and limits

Baseline Glexia take generated from the official MITRE ATT&CK STIX object, source hash, tactics, platforms, and detection fields. It is safe to replace with a richer model-generated take for the same source hash later.

This baseline take is source-grounded and schema-validated, but it does not include environment-specific telemetry, incident evidence, or threat-intelligence corroboration.

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Official MITRE ATT&CK definition

Ryuk

Ryuk is a ransomware designed to target enterprise environments that has been used in attacks since at least 2018. Ryuk shares code similarities with Hermes ransomware.[1][2][3]

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

How security teams should use this page

Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.

ATT&CK relationship table

Techniques used

This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.

22 rows
DomainIDNameRelationship / procedure
EnterpriseT1027Obfuscated Files or Information

Ryuk can use anti-disassembly and code transformation obfuscation techniques.CitationCrowdStrike Wizard Spider October 2020

EnterpriseT1106Native API

Ryuk has used multiple native APIs including ShellExecuteW to run executables,GetWindowsDirectoryW to create folders, and VirtualAlloc, WriteProcessMemory, and CreateRemoteThread for process injection.[1]

EnterpriseT1057Process Discovery

Ryuk has called CreateToolhelp32Snapshot to enumerate all running processes.[1]

EnterpriseT1021.002SMB/Windows Admin SharesSub-technique

Ryuk has used the C$ network share for lateral movement.[4]

EnterpriseT1083File and Directory Discovery

Ryuk has enumerated files and folders on all mounted drives.[1]

EnterpriseT1490Inhibit System Recovery

Ryuk has used vssadmin Delete Shadows /all /quiet to to delete volume shadow copies and vssadmin resize shadowstorage to force deletion of shadow copies created by third-party applications.[1]

EnterpriseT1614.001System Language DiscoverySub-technique

Ryuk has been observed to query the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Language and the value InstallLanguage. If the machine has the value 0x419 (Russian), 0x422 (Ukrainian), or 0x423 (Belarusian), it stops execution.[1]

EnterpriseT1078.002Domain AccountsSub-technique

Ryuk can use stolen domain admin accounts to move laterally within a victim domain.CitationANSSI RYUK RANSOMWARE

EnterpriseT1059.003Windows Command ShellSub-technique

Ryuk has used cmd.exe to create a Registry entry to establish persistence.[1]

EnterpriseT1036.005Match Legitimate Resource Name or LocationSub-technique

Ryuk has constructed legitimate appearing installation folder paths by calling GetWindowsDirectoryW and then inserting a null byte at the fourth character of the path. For Windows Vista or higher, the path would appear as C:\Users\Public.[1]

EnterpriseT1489Service Stop

Ryuk has called kill.bat for stopping services, disabling services and killing processes.[1]

EnterpriseT1222.001Windows PermissionsSub-technique

Ryuk can launch icacls /grant Everyone:F /T /C /Q to delete every access-based restrictions on files and directories.CitationANSSI RYUK RANSOMWARE

EnterpriseT1685Disable or Modify Tools

Ryuk has stopped services related to anti-virus.[2]

EnterpriseT1053.005Scheduled TaskSub-technique

Ryuk can remotely create a scheduled task to execute itself on a system.CitationANSSI RYUK RANSOMWARE

EnterpriseT1680Local Storage Discovery

Ryuk has called GetLogicalDrives to emumerate all mounted drives, and GetDriveTypeW to determine the drive type.[1]

EnterpriseT1205Traffic Signaling

Ryuk has used Wake-on-Lan to power on turned off systems for lateral movement.[4]

EnterpriseT1486Data Encrypted for Impact

Ryuk has used a combination of symmetric (AES) and asymmetric (RSA) encryption to encrypt files. Files have been encrypted with their own AES key and given a file extension of .RYK. Encrypted directories have had a ransom note of RyukReadMe.txt written to the directory.[1]CitationCrowdStrike Wizard Spider October 2020

EnterpriseT1055Process Injection

Ryuk has injected itself into remote processes to encrypt files using a combination of VirtualAlloc, WriteProcessMemory, and CreateRemoteThread.[1]

EnterpriseT1036Masquerading

Ryuk can create .dll files that actually contain a Rich Text File format document.CitationANSSI RYUK RANSOMWARE

EnterpriseT1547.001Registry Run Keys / Startup FolderSub-technique

Ryuk has used the Windows command line to create a Registry entry under HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run to establish persistence.[1]

EnterpriseT1016System Network Configuration Discovery

Ryuk has called GetIpNetTable in attempt to identify all mounted drives and hosts that have Address Resolution Protocol (ARP) entries.[1][4]

EnterpriseT1134Access Token Manipulation

Ryuk has attempted to adjust its token privileges to have the SeDebugPrivilege.[1]

Associated objects

Groups, software, and campaigns

GroupEnterprise

G0037: FIN6

FIN6 is a cyber crime group that has stolen payment card data and sold it for profit on underground marketplaces. This group has aggressively targeted and compromised point of sale (PoS) systems in the hospitality and retail sectors.[1][2]

GroupEnterprise

G0102: Wizard Spider

Wizard Spider is a Russia-based financially motivated threat group originally known for the creation and deployment of TrickBot since at least 2016. Wizard Spider possesses a diverse arsenal of tools and has conducted ransomware campaigns against a variety of organizations, ranging from major corporations to hospitals.[1][2][3]

Relationship explorer

All related ATT&CK context

uses · GroupG0037: FIN6Enterpriseuses · GroupG0102: Wizard SpiderEnterpriseuses · TechniqueT1027: Obfuscated Files or InformationEnterpriseuses · TechniqueT1106: Native APIEnterpriseuses · TechniqueT1057: Process DiscoveryEnterpriseuses · TechniqueT1021.002: SMB/Windows Admin SharesEnterpriseuses · TechniqueT1083: File and Directory DiscoveryEnterpriseuses · TechniqueT1490: Inhibit System RecoveryEnterpriseuses · TechniqueT1614.001: System Language DiscoveryEnterpriseuses · TechniqueT1078.002: Domain AccountsEnterpriseuses · TechniqueT1059.003: Windows Command ShellEnterpriseuses · TechniqueT1036.005: Match Legitimate Resource Name or LocationEnterpriseuses · TechniqueT1489: Service StopEnterpriseuses · TechniqueT1222.001: Windows PermissionsEnterpriseuses · TechniqueT1685: Disable or Modify ToolsEnterpriseuses · TechniqueT1053.005: Scheduled TaskEnterpriseuses · TechniqueT1680: Local Storage DiscoveryEnterpriseuses · TechniqueT1205: Traffic SignalingEnterpriseuses · TechniqueT1486: Data Encrypted for ImpactEnterpriseuses · TechniqueT1055: Process InjectionEnterpriseuses · TechniqueT1036: MasqueradingEnterpriseuses · TechniqueT1547.001: Registry Run Keys / Startup FolderEnterpriseuses · TechniqueT1016: System Network Configuration DiscoveryEnterpriseuses · TechniqueT1134: Access Token ManipulationEnterprise
Change history

Object version and sync metadata

The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates.

ATT&CK release
19.2
Object version
1.4
Created
Modified
Raw hash
bbedbff5a2d4dac0...
Imported snapshots across ATT&CK releases(2)
ReleaseBundle importedObject versionModifiedStatusRaw hash
19.21.4Current bundlebbedbff5a2d4…
19.11.4Older bundlebbedbff5a2d4…
Raw source

Mirrored ATT&CK source object

The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.

Open mirrored raw JSONOpen MITRE-hosted copy
Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

  1. [1]
    CrowdStrike Ryuk January 2019

    Hanel, A. (2019, January 10). Big Game Hunting with Ryuk: Another Lucrative Targeted Ransomware. Retrieved May 12, 2020.

    Open source URL
  2. [2]
    FireEye Ryuk and Trickbot January 2019

    Goody, K., et al (2019, January 11). A Nasty Trick: From Credential Theft Malware to Business Disruption. Retrieved May 12, 2020.

    Open source URL
  3. [3]
    FireEye FIN6 Apr 2019

    McKeague, B. et al. (2019, April 5). Pick-Six: Intercepting a FIN6 Intrusion, an Actor Recently Tied to Ryuk and LockerGoga Ransomware. Retrieved April 17, 2019.

    Open source URL
  4. [4]
    Bleeping Computer - Ryuk WoL

    Abrams, L. (2021, January 14). Ryuk Ransomware Uses Wake-on-Lan To Encrypt Offline Devices. Retrieved February 11, 2021.

    Open source URL
  5. [5]
    Ryuk

    (Citation: CrowdStrike Ryuk January 2019) (Citation: Bleeping Computer - Ryuk WoL)

  6. [6]
    mitre-attackS0446
    Open source URL
Source and licensing

Source: MITRE ATT&CK®. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation. Glexia is not affiliated with or endorsed by MITRE.

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