TMA-CHROME-4.2.1

Ensure 'Control use of the Serial API' is set to 'Enabled: Do not allow any site to request access to serial ports via the Serial API'

MediumLevel 2Automatedchrome

Description

This setting controls website access and use of the system serial port. - Do not allow any site to request access to serial ports via the Serial API (2) - Allow sites to ask the user to grant access to a serial port (3) The recommended state for this setting is: Do not allow any site to request access to serial ports via the Serial API (2) NOTE: If more granular control is needed (per website) then this setting can b... Rationale: Preventing access to system serial ports may prevent malicious sites from using these ports and accessing the devices attached. Audit reads the Group Policy registry value and prints 'compliant', 'unset' (policy not configured, reported as FAIL) or the non-compliant value. Registry value: HKLM\SOFTWARE\Policies\Google\Chrome:DefaultSerialGuardSetting (REG_DWORD); compliant when it is 2. Remediation writes 2 locally; in a domain set it through the ADMX so Group Policy does not revert it.

How it is checked

Audit method: Windows registry

registry

$v = (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome' -Name 'DefaultSerialGuardSetting' -ErrorAction SilentlyContinue).'DefaultSerialGuardSetting'; if ($null -eq $v) { 'unset' } elseif (($null -ne $v -and @(2) -contains [int64]$v)) { 'compliant' } else { "non-compliant: $v" }

Expected output: compliant

How it is fixed

Fix method: Shell command

shell

$p = 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome'; if (-not (Test-Path -Path $p)) { New-Item -Path $p -Force | Out-Null }; New-ItemProperty -Path $p -Name 'DefaultSerialGuardSetting' -Value 2 -PropertyType DWord -Force | Out-Null

Properties

Operating systems: Any
Tags: chromebrowsercis-l2
Reference: CIS Google Chrome Benchmark v3.0.0 - 4.2.1 Ensure 'Control use of the Serial API' is set to 'Enabled: Do not allow any site to request access to serial ports via the Serial API'

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target chrome --level 2