Adversaries may use [Valid Accounts](https://attack.mitre.org/techniques/T1078) to log into remote machines using Secure Shell (SSH). The adversary may then perform actions as the logged-on user. SSH is a protocol that allows authorized users to open remote shells on other computers. Many Linux and macOS versions come with SSH installed by default, although typically disabled until the user enables it. On ESXi, SSH can be enabled either directly on the host (e.g., via `vim-cmd hostsvc/enable_ssh`) or via vCenter.(Citation: Sygnia ESXi Ransomware 2025)(Citation: TrendMicro ESXI Ransomware)(Citation: Sygnia Abyss Locker 2025) The SSH server can be configured to use standard password authentication or public-private keypairs in lieu of or in addition to a password. In this authentication scenario, the user’s public key must be in a special file on the computer running the server that lists which keypairs are allowed to login as that user (i.e., [SSH Authorized Keys](https://attack.mitre.org/techniques/T1098/004)).

Linked Issues

Issuelinks
Linktype Issue
is related to Techniques
is blocked by Disable or Remove Feature or Program
is blocked by Multi-factor Authentication
is blocked by Behavioral Detection of Remote SSH Logins Followed by Post-Login Execution
is blocked by User Account Management
is blocked by Asset Inventories
is blocked by Access Restriction For Change
is blocked by Secure Baseline Configurations
is blocked by Continuous Monitoring
is blocked by Use of External Technology Assets, Applications and/or Services (TAAS)
is blocked by Separation of Duties (SoD)
is blocked by Identification & Authentication for Organizational Users
is blocked by Authenticator Management
is blocked by Account Management
is blocked by Access Enforcement
is blocked by Least Privilege
is blocked by Account Lockout
is blocked by Remote Access
is blocked by Vulnerability Scanning
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