Fsteam

MITRE ATT&CK does not currently catalogue Fsteam, 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: low. Treat it as orientation, not attribution.

1. T1059.001 PowerShell Execution

   What they do: fsteam uses PowerShell scripts to execute malicious commands and propagate payloads across compromised hosts.

   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: fsteam modifies registry run keys to ensure malware execution upon system reboot.

   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: fsteam disables security tools like antivirus software and monitoring agents to evade detection.

   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. T1027.013 Encrypted/Encoded File Stealth

   What they do: fsteam encrypts or encodes victim files with custom ransomware payloads before deletion.

   What that means: Adversaries may encrypt or encode files to obfuscate strings, bytes, and other specific patterns to impede detection.

5. T1070.004 File Deletion Stealth

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

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

6. T1018 Remote System Discovery Discovery

   What they do: fsteam performs remote system discovery to identify additional hosts within the victim network.

   What that means: Adversaries may attempt to get a listing of other systems by IP address, hostname, or other logical identifier on a network that may be used for Lateral Movement from the current system.

7. T1135 Network Share Discovery Discovery

   What they do: fsteam scans network shares to discover accessible directories and victim files for targeting.

   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.

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

   What they do: fsteam uses SMB/Windows Admin Shares for lateral movement between compromised machines.

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

9. T1486 Data Encrypted for Impact Impact

   What they do: fsteam encrypts victim files using strong symmetric encryption to maximize impact and ransom demand.

   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: fsteam calls system recovery inhibitors like shutdown scripts to prevent restoration attempts.

    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.