# Az - Application Proxy

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## Basic Information

[From the docs:](https://learn.microsoft.com/en-us/entra/identity/app-proxy/application-proxy)

Azure Active Directory's Application Proxy provides **secure remote access to on-premises web applications**. After a **single sign-on to Azure AD**, users can access both **cloud** and **on-premises applications** through an **external URL** or an internal application portal.

It works like this:

<figure><img src="../../../images/image (186).png" alt=""><figcaption></figcaption></figure>

1. After the user has accessed the application through an endpoint, the user is directed to the **Azure AD sign-in page**.
2. After a **successful sign-in**, Azure AD sends a **token** to the user's client device.
3. The client sends the token to the **Application Proxy service**, which retrieves the user principal name (UPN) and security principal name (SPN) from the token. **Application Proxy then sends the request to the Application Proxy connector**.
4. If you have configured single sign-on, the connector performs any **additional authentication** required on behalf of the user.
5. The connector sends the request to the **on-premises application**.
6. The **response** is sent through the connector and Application Proxy service **to the user**.

## Enumeration

```bash
# Enumerate applications with application proxy configured
Get-AzureADApplication | %{try{Get-AzureADApplicationProxyApplication -ObjectId $_.ObjectID;$_.DisplayName;$_.ObjectID}catch{}}

# Get applications service principal
Get-AzureADServicePrincipal -All $true | ?{$_.DisplayName -eq "Name"}

# Use the following ps1 script from https://learn.microsoft.com/en-us/azure/active-directory/app-proxy/scripts/powershell-display-users-group-of-app
# to find users and groups assigned to the application. Pass the ObjectID of the Service Principal to it
Get-ApplicationProxyAssignedUsersAndGroups -ObjectId <object-id>
```

## References

- [https://learn.microsoft.com/en-us/azure/active-directory/app-proxy/application-proxy](https://learn.microsoft.com/en-us/azure/active-directory/app-proxy/application-proxy)

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