Yurei

MITRE ATT&CK does not currently catalogue Yurei, so this is our assessment of the techniques it uses, drawn from public reporting. The techniques themselves, and every "what that means" definition below, come from MITRE ATT&CK v19.2. Confidence: medium. Treat it as orientation, not attribution.

1. T1059.001 PowerShell Execution

   What they do: yurei executes malicious PowerShell scripts to stage ransomware payloads and evade detection.

   What that means: Adversaries may abuse PowerShell commands and scripts for execution.

2. T1106 Native API Execution

   What they do: yurei leverages native API calls to interact with Windows services and disable security tools.

   What that means: Adversaries may interact with the native OS application programming interface (API) to execute behaviors.

3. T1112 Modify Registry PersistenceDefense Impairment

   What they do: yurei modifies registry run keys to ensure ransomware execution upon system reboot.

   What that means: Adversaries may interact with the Windows Registry as part of a variety of other techniques to aid in defense evasion, persistence, and execution.

4. T1685 Disable or Modify Tools Defense Impairment

   What they do: yurei disables antivirus and monitoring tools by terminating processes and modifying security configurations.

   What that means: Adversaries may disable, degrade, or tamper with security tools or applications (e.g., endpoint detection and response (EDR) tools, intrusion detection systems (IDS), antivirus, logging agents, sensors, etc.) to impair or reduce visibility of defensive capabilities.

5. T1070.004 File Deletion Stealth

   What they do: yurei deletes Volume Shadow Copies and backup files to prevent data recovery.

   What that means: Adversaries may delete files left behind by the actions of their intrusion activity.

6. T1021.002 SMB/Windows Admin Shares Lateral Movement

   What they do: yurei spreads laterally via SMB/Windows Admin Shares to compromise additional networked systems.

   What that means: Adversaries may use Valid Accounts to interact with a remote network share using Server Message Block (SMB).

7. T1048 Exfiltration Over Alternative Protocol Exfiltration

   What they do: yurei encrypts victim files using symmetric cryptography keys derived from victim data.

   What that means: Adversaries may steal data by exfiltrating it over a different protocol than that of the existing command and control channel.

8. T1567.002 Exfiltration to Cloud Storage Exfiltration

   What they do: yurei exfiltrates sensitive victim data before encryption to increase ransom pressure.

   What that means: Adversaries may exfiltrate data to a cloud storage service rather than over their primary command and control channel.

9. T1486 Data Encrypted for Impact Impact

   What they do: yurei encrypts victim files using custom ransomware binaries, targeting documents and system data for impact.

   What that means: Adversaries may encrypt data on target systems or on large numbers of systems in a network to interrupt availability to system and network resources.

10. T1490 Inhibit System Recovery Impact

    What they do: yurei calls system recovery inhibitors like vssadmin to disable Volume Shadow Copy restoration.

    What that means: Adversaries may delete or remove built-in data and turn off services designed to aid in the recovery of a corrupted system to prevent recovery.

Software Yurei has been seen using, grouped by what it is used for. Legitimate administration tools appear here because these actors routinely abuse them — presence in this list is not itself malicious.

Tool data from Ransomware Tool Matrix by BushidoUK, licensed CC BY 4.0. Grouped by purpose and matched to this group by Breach House.