Ensure 'Allow remote users to interact with elevated windows in remote assistance sessions' is set to 'Disabled'

MediumLevel 1Automatedchrome

Description

Google Chrome can be set to run the remote assistance host in a process with uiAccess permissions. This allows remote users to interact with elevated windows on the local user's desktop. If this setting is disabled, the remote assistance host will run in the user's context. Furthermore, remote users cannot interact with elevated windows on the desktop. The recommended state for this setting is: Disabled (0) Rationale: Remote users shall not be able to escalate privileges. 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:RemoteAccessHostAllowUiAccessForRemoteAssistance (REG_DWORD); compliant when it is 0. Remediation writes 0 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

$v = (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome' -Name 'RemoteAccessHostAllowUiAccessForRemoteAssistance' -ErrorAction SilentlyContinue).'RemoteAccessHostAllowUiAccessForRemoteAssistance'; if ($null -eq $v) { 'unset' } elseif (($null -ne $v -and @(0) -contains [int64]$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 'RemoteAccessHostAllowUiAccessForRemoteAssistance' -Value 0 -PropertyType DWord -Force | Out-Null

Properties

Operating systems: Any
Tags: chromebrowsercis-l1
Reference: CIS Google Chrome Benchmark v3.0.0 - 2.8.2 Ensure 'Allow remote users to interact with elevated windows in remote assistance sessions' is set to 'Disabled'

Check this host

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

shell

tmaegis scan --target chrome