How to develop a basic Windows plugin

In this tutorial it will be shown how to develop a basic plugin that collects the list of domain users and groups in a Windows Active Directory domain. It can be considered as a guideline to create additional plugins for Windows.

1. Scaffolding

The first steps consists of creating the structure of the plugin based on the sample plugin already made available. The plugin name will be windows_domain_users so the command to be executed is the following:

user@master-node:~/rusthunter$ cp -r app/src/plugins/sample app/src/plugins/windows/domain_users

The plugin folder contains the mod.rs file which provides the plugin logic:

user@master-node:~/rusthunter$ ls -al app/src/plugins/windows/domain_users
mod.rs

2. Customization

The file app/src/plugins/windows/domain_users/mod.rs must be properly customized to collect the desired data on the target machine.

1. Replace all the occurrencies of the struct name SamplePlugin with WindowsDomainUsers. It can be easily done via the command:

user@master-node:~/rusthunter$ sed -i 's/SamplePlugin/WindowsDomainUsers/g' app/src/plugins/windows/domain_users/mod.rs

1. Replace the plugin name sample_plugin with windows_domain_users (Line 10).

2. Replace the plugin description Sample description with Domain users and groups (Line 14).

3. Replace the plugin operating system OS::Unknown with OS::Windows (Line 18).

4. Replace the plugin command sample command with Get-ADuser -Filter * | Select-Object Name,ObjectClass,Enabled | Sort-Object -Property Name | ConvertTo-Json (Line 22).

5. Replace Ok(()) (Line 30) with the correct output processing function. Since the output of the command will be already a JSON object so the needed function is self._convert_json_string(output).

Finally, the code should be this:

use serde_json::Value;

use crate::config::Config;
use crate::plugins::{Plugin, OS};

pub struct WindowsDomainUsers {}

impl Plugin for WindowsDomainUsers {
    fn name(&self) -> &str {
        &"windows_domain_users"
    }

    fn description(&self) -> &str {
        &"Domain users and groups"
    }

    fn os(&self) -> OS {
        OS::Windows
    }

    fn run(&self, _config: &Config, _binary_directory: &str) -> Result<Value, String> {
        let command = "Get-ADuser -Filter * | Select-Object Name,ObjectClass,Enabled | Sort-Object -Property Name | ConvertTo-Json";
        match self.execute_command(&command) {
            Ok(output) => self.process(&output),
            Err(e) => Err(e),
        }
    }

    fn process(&self, output: &str) -> Result<Value, String> {
        self._convert_json_string(output)
    }
}

impl WindowsDomainUsers {
    pub fn new() -> Self {
        WindowsDomainUsers {}
    }
}

3. Unlocking

The plugin logic has been defined but the plugin must be linked to the main application logic, so:

1. Add the line pub mod domain_users; to the app/src/plugins/linux/mod.rs file.

2. Update the execute method in the app/src/lib.rs file:

   • Below the comment // Import Windows plugins add the line domain_users::WindowsDomainUsers,
   • Below the comment // Instantiate Windows plugins add the line let windows_domain_users = WindowsDomainUsers::new();
   • Below the comment // Execute Windows plugins add the line &windows_domain_users,

Finally, the code should be like the following:

if #[cfg(target_os = "windows")] {
    use crate::plugins::windows::{
        // Import Windows plugins
        users::WindowsUsers,
        // ...
        domain_users::WindowsDomainUsers, // <- New module
        // ...
    };

    // Instantiate Windows plugins
    let windows_users = WindowsUsers::new();
    // ...
    let windows_domain_users = WindowsDomainUsers::new(); // <- New module
    // ...
    let plugins: Vec<&dyn Plugin> = vec![
                                            // Execute Windows plugins
                                            &windows_users,
                                            // ...
                                            &windows_domain_users, // <- New module
                                            // ...
                                        ];
    } else if #[cfg(target_os = "linux")] {

4. Configuration

In order to enable/disable the plugin execution, it is necessary to add to the config.ini INI file the following block:

[windows_domain_users]
enabled = true

5. Re-building

Execute the following command to rebuild the framework (requires Docker) to include the new plugin:

user@master-node:~/rusthunter$ sudo ./rusthunter.sh build

The Docker image peco602/rust-universal-compiler will be downloaded (it can take some time) and used to rebuild the Rust code for all the platforms.