Mountlocker

MITRE ATT&CK does not currently catalogue Mountlocker, 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: mountlocker executes PowerShell scripts to propagate payloads and disable security tools across victim systems.

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

2. T1547.001 Registry Run Keys / Startup Folder PersistencePrivilege Escalation

   What they do: mountlocker leverages registry run keys to ensure malware execution upon system reboot for persistence.

   What that means: Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key.

3. T1685 Disable or Modify Tools Defense Impairment

   What they do: mountlocker disables antivirus and monitoring tools by terminating processes and modifying system 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.

4. T1070.004 File Deletion Stealth

   What they do: mountlocker deletes Volume Shadow Copies and backup files via command-line utilities to prevent recovery.

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

5. T1135 Network Share Discovery Discovery

   What they do: mountlocker uses network share discovery to locate and encrypt files across mapped drives and shared directories.

   What that means: Adversaries may look for folders and drives shared on remote systems as a means of identifying sources of information to gather as a precursor for Collection and to identify potential systems of interest for Lateral Movement.

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

   What they do: mountlocker moves laterally through SMB/Windows Admin Shares to compromise additional networked machines.

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

7. T1486 Data Encrypted for Impact Impact

   What they do: mountlocker encrypts victim documents and data using custom ransomware routines to maximize impact and extortion.

   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.

8. T1490 Inhibit System Recovery Impact

   What they do: mountlocker invokes system shutdown commands and service termination to disrupt operations and hinder recovery.

   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 Mountlocker 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.

Crowdsourced payment data from Ransomwhere, licensed CC BY 4.0. Figures are what has been reported and attributed to this family, not a confirmed total. Cite as: Cable, Jack. (2024). Ransomwhere: A Crowdsourced Ransomware Payment Dataset (1.1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.6512122