Command and Scripting Interpreter: Hypervisor CLI

Adversaries may abuse hypervisor command line interpreters (CLIs) to execute malicious commands. Hypervisor CLIs typically enable a wide variety of functionality for managing both the hypervisor itself and the guest virtual machines it hosts.

For example, on ESXi systems, tools such as esxcli and vim-cmd allow administrators to configure firewall rules and log forwarding on the hypervisor, list virtual machines, start and stop virtual machines, and more.[1][2][3] Adversaries may be able to leverage these tools in order to support further actions, such as File and Directory Discovery or Data Encrypted for Impact.

ID: T1059.012
Sub-technique of:  T1059
Tactic: Execution
Platforms: ESXi
Contributors: Janantha Marasinghe; Liran Ravich, CardinalOps
Version: 1.0
Created: 26 March 2025
Last Modified: 15 April 2025

Procedure Examples

ID Name Description
S1096 Cheerscrypt

Cheerscrypt has leveraged esxcli in order to terminate running virtual machines.[4]

S1073 Royal

Royal ransomware uses esxcli to gather a list of running VMs and terminate them.[5]

G1048 UNC3886

UNC3886 has used the esxcli command line utility to modify firewall rules, install malware, and for artifact removal.[6][7]

S1218 VIRTUALPIE

VIRTUALPIE is capable of command line execution on compromised ESXi servers.[6]

Mitigations

This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.

Detection Strategy

ID Name Analytic ID Analytic Description
DET0558 Detection Strategy for ESXi Hypervisor CLI Abuse AN1537

Detects suspicious use of ESXi native CLI tools like esxcli and vim-cmd by unauthorized users or outside expected maintenance windows. Focus is on actions such as stopping VMs, reconfiguring network/firewall settings, and enabling SSH or logging.

References