The ESXi host must configure a persistent log location for all locally stored logs.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-258797	ESXI-80-000243	SV-258797r1003575_rule		Medium

Description
ESXi can be configured to store log files on an in-memory file system. This occurs when the host's "/scratch" directory is linked to "/tmp/scratch". When this is done, only a single day's worth of logs are stored at any time. In addition, log files will be reinitialized upon each reboot. This presents a security risk as user activity logged on the host is only stored temporarily and will not persist across reboots. This can also complicate auditing and make it harder to monitor events and diagnose issues. ESXi host logging should always be configured to a persistent datastore. Note: Scratch space is configured automatically during installation or first boot of an ESXi host and does not usually need to be configured manually. If ESXi is installed on an SD card or USB device, a persistent log location may not be configured upon install as normal.

Description

ESXi can be configured to store log files on an in-memory file system. This occurs when the host's "/scratch" directory is linked to "/tmp/scratch". When this is done, only a single day's worth of logs are stored at any time. In addition, log files will be reinitialized upon each reboot. This presents a security risk as user activity logged on the host is only stored temporarily and will not persist across reboots. This can also complicate auditing and make it harder to monitor events and diagnose issues. ESXi host logging should always be configured to a persistent datastore. Note: Scratch space is configured automatically during installation or first boot of an ESXi host and does not usually need to be configured manually. If ESXi is installed on an SD card or USB device, a persistent log location may not be configured upon install as normal.

STIG	Date
VMware vSphere 8.0 ESXi Security Technical Implementation Guide	2024-07-11

Details

Check Text ( C-62537r933450_chk )
From the vSphere Client, go to Hosts and Clusters. Select the ESXi Host >> Configure >> System >> Advanced System Settings. Select the "Syslog.global.logDir" value and verify it is set to a persistent location. If the value of the setting is "[] /scratch/logs", verify the advanced setting "ScratchConfig.CurrentScratchLocation" is not set to "/tmp/scratch". This is a nonpersistent location. If "Syslog.global.logDir" is not configured to a persistent location, this is a finding. or From a PowerCLI command prompt while connected to the ESXi host, run the following commands: $esxcli = Get-EsxCli -v2 $esxcli.system.syslog.config.get.Invoke() \| Select LocalLogOutput,LocalLogOutputIsPersistent If the "LocalLogOutputIsPersistent" value is not true, this is a finding.

Check Text ( C-62537r933450_chk )

From the vSphere Client, go to Hosts and Clusters.

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

Select the "Syslog.global.logDir" value and verify it is set to a persistent location.

If the value of the setting is "[] /scratch/logs", verify the advanced setting "ScratchConfig.CurrentScratchLocation" is not set to "/tmp/scratch". This is a nonpersistent location.

If "Syslog.global.logDir" is not configured to a persistent location, this is a finding.

or

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

$esxcli = Get-EsxCli -v2
$esxcli.system.syslog.config.get.Invoke() | Select LocalLogOutput,LocalLogOutputIsPersistent

If the "LocalLogOutputIsPersistent" value is not true, this is a finding.

Fix Text (F-62446r1003544_fix)
From the vSphere Client, go to Hosts and Clusters. Select the ESXi Host >> Configure >> System >> Advanced System Settings. Click "Edit". Select the "Syslog.global.logDir" value and set it to a known persistent location. An example is shown below, where 51dda02d-fade5016-8a08-005056171889 is the UUID of the target datastore: /vmfs/volumes/51dda02d-fade5016-8a08-005056171889 or From a PowerCLI command prompt while connected to the ESXi host, run the following command: Get-VMHost \| Get-AdvancedSetting -Name Syslog.global.logDir \| Set-AdvancedSetting -Value "New Log Location" Note: The new location should not include a subfolder as enabling audit logging will create a folder and will fail if a subfolder is specified.

Fix Text (F-62446r1003544_fix)

From the vSphere Client, go to Hosts and Clusters.

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

Click "Edit". Select the "Syslog.global.logDir" value and set it to a known persistent location.

An example is shown below, where 51dda02d-fade5016-8a08-005056171889 is the UUID of the target datastore:

/vmfs/volumes/51dda02d-fade5016-8a08-005056171889

or

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

Get-VMHost | Get-AdvancedSetting -Name Syslog.global.logDir | Set-AdvancedSetting -Value "New Log Location"

Note: The new location should not include a subfolder as enabling audit logging will create a folder and will fail if a subfolder is specified.