The ESXi host must prohibit the reuse of passwords within five iterations.

If a user or root used the same password continuously or was allowed to change it back shortly after being forced to change it to something else, it would provide a potential intruder with the opportunity to keep guessing at one user's password until it was guessed correctly.

From the vSphere Client, go to Hosts and Clusters.

Select the ESXi Host >> Configure >> System >> Advanced System Settings.

Select the "Security.PasswordHistory" value and verify it is set to "5".

or

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

Get-VMHost | Get-AdvancedSetting -Name Security.PasswordHistory

If the "Security.PasswordHistory" setting is not set to "5" this is a finding.

From the vSphere Client, go to Hosts and Clusters.

Select the ESXi Host >> Configure >> System >> Advanced System Settings.

Click "Edit". Select the "Security.PasswordHistory" value and configure it to "5".

or

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

Get-VMHost | Get-AdvancedSetting -Name Security.PasswordHistory | Set-AdvancedSetting -Value 5