The ESXi host Secure Shell (SSH) daemon must set a timeout count on idle sessions.

Setting a timeout ensures that a user login will be terminated as soon as the "ClientAliveCountMax" is reached.

From an ESXi shell, run the following command:

# esxcli system ssh server config list -k clientalivecountmax

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 'clientalivecountmax'}

Example result:

clientalivecountmax 3

If "clientalivecountmax" is not configured to "3", this is a finding.

From an ESXi shell, run the following command:

# esxcli system ssh server config set -k clientalivecountmax -v 3

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 = 'clientalivecountmax' $arguments.value = '3' $esxcli.system.ssh.server.config.set.Invoke($arguments)