The ESXi host Secure Shell (SSH) daemon must not allow host-based authentication.

SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts. SSH's cryptographic host-based authentication is more secure than ".rhosts" authentication since hosts are cryptographically authenticated. However, it is not recommended that hosts unilaterally trust one another, even within an organization.

From an ESXi shell, run the following command:

# esxcli system ssh server config list -k hostbasedauthentication

or

From a PowerCLI command prompt while connected to the ESXi host, run the following commands:

$esxcli = Get-EsxCli -v2 $esxcli.system.ssh.server.config.list.invoke() | Where-Object {$_.Key -eq 'hostbasedauthentication'}

Example result:

hostbasedauthentication no

If "hostbasedauthentication" is not configured to "no", this is a finding.

From an ESXi shell, run the following command:

# esxcli system ssh server config set -k hostbasedauthentication -v no

or

From a PowerCLI command prompt while connected to the ESXi host, run the following commands:

$esxcli = Get-EsxCli -v2 $arguments = $esxcli.system.ssh.server.config.set.CreateArgs() $arguments.keyword = 'hostbasedauthentication' $arguments.value = 'no' $esxcli.system.ssh.server.config.set.Invoke($arguments)