> For the complete documentation index, see [llms.txt](https://rfc1918.gitbook.io/offsec/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://rfc1918.gitbook.io/offsec/execution/powershell/c-assembly-in-powershell/unsafenativemethods.md).

# UnsafeNativeMethods

To perform a dynamic lookup of function addresses, the operating system provides two special Win32 APIs called GetModuleHandle and GetProcAddress.

{% hint style="info" %}
GetModuleHandle obtains a handle to the specified DLL, which is the memory address of the DLL.

To find the address of a specific function we’ll pass the DLL handle, and the function name to GetProcAddress, which will return the function address.
{% endhint %}

## Searching preload assemblies with GetModuleHandle and GetProcAddress

```powershell
$assemblies = [AppDomain]::CurrentDomain.GetAssemblies()

$assemblies | 
    ForEach-Object {
        $_.GlobalAssemblyCache
        $_.Location
        $_.GetTypes() | 
            ForEach-Object {
                $_ | Get-Member -static | Where-Object {
                    $_.TypeName.Contains('Unsafe') -and $_.Name.Contains('GetProcAddress') -or $_.Name.Contains('GetModuleHandle')
                } | Format-Table *
            } 2> $null 
    }
```

<figure><img src="/files/y0r70LUht1diMSYWwQ8f" alt=""><figcaption></figcaption></figure>

{% hint style="warning" %}
The code does not run in *PowerShell Core* as`System.dll` isn't installed into the Global Assembly Cache (GAC) there by default.
{% endhint %}

## Lookup function address

```powershell
function GetProcAddress {
    Param (
        [OutputType([IntPtr])]

        [Parameter( Position = 0, Mandatory = $true)]
        [String]
        $moduleName, 

        [Parameter( Position = 1, Mandatory = $true)]
        [String]
        $functionName
    )

    # Get reference to System.dll in the GAC
    $sysassembly = [System.AppDomain]::CurrentDomain.GetAssemblies() | Where-Object {
        $_.GlobalAssemblyCache -and $_.Location.Split('\\')[-1] -eq 'System.dll'
    }

    $types = $sysassembly.GetTypes()
    $unsafenativemethods = ForEach ($type in $types) {
        $type | Where-Object {$_.FullName -like '*NativeMethods' -and $_.Fullname -like '*Win32*' -and $_.Fullname -like '*Un*'}
    }

    # Get reference to GetModuleHandle and GetProcAddress methods
    $modulehandle = $unsafenativemethods.GetMethods() | Where-Object {$_.Name -like '*Handle' -and $_.Name -like '*Module*'}
    $procaddress = $unsafenativemethods.GetMethods() | Where-Object {$_.Name -like '*Address' -and $_.Name -like '*Proc*'} | Select-Object -First 1

    # Get handle on module specified
    $module = $modulehandle.Invoke($null, @($moduleName))
    $procaddress.Invoke($null, @($module, $functionName))
}
```

## Next steps

{% content-ref url="/pages/RABbZsHcpwpaeXvJA0Li" %}
[DelegateType Reflection](/offsec/execution/powershell/c-assembly-in-powershell/delegatetype-reflection.md)
{% endcontent-ref %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://rfc1918.gitbook.io/offsec/execution/powershell/c-assembly-in-powershell/unsafenativemethods.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.