Installing Authentication Verifier Agent on Linux (Debian Distribution)

This document is for:

Invicti Enterprise On-Demand, Invicti Enterprise On-Premises

You can download and install authentication verifier agents to verify that you run authenticated scans in your local environment.

In order to scan a website located on your internal network, and not accessible from the internet, you can install and configure a scan agent on your network. The agent will conduct the actual scan job and then report the results back to Invicti Enterprise.
You can download and install an internal verifier agent to perform the authentication, so you can make sure that your scan is authenticated.

For further information about the internal authentication verifier, see Streamline authenticated scanning with Invicti’s verifier agents.

To install the authentication verifier agent on the Linux operating system, you must install some dependencies on the system, such as .NET, Mono. Mono is a software platform designed to allow developers to easily create cross-platform applications that become part of the .NET Foundation.

This topic explains how to install, update, and uninstall authentication verifier agents on Linux (Debian). Using Windows? See Installing Authentication Verifier Agents. For the RedHat distributions, see Installing Authentication Verifier Agent on Linux (RedHat Distribution).

The Authentication Verifier Agent is an optional component.

Download and install the authentication verifier agent if you need to scan websites with form or basic authentication or OAuth2. The authentication verifier agents also work for the Authentication Profiles, Custom Scripts for Form Authentication, CyberArk Vault, HashiCorp Vault, and AzureKey Vault.

Downloading and configuring authentication verifier agent on Linux

There are 3 steps in this process:

Downloading an authentication verifier agent
Installing an authentication verifier agent
Setting an authentication verifier agent as a Linux Service

Prerequisites

Hardware Requirements

1.4 GHz Processor (2.0 GHz or faster recommended)
4 GB RAM or higher recommended
10 GB Free Disk space for each internal agent

Network Requirements

The Agent should be configured so that it can reach your internal website through HTTP/HTTPS.
The Agent needs to be able to access the Invicti Enterprise Authentication Verifier Server’s HTTP(S) (443) port.

Allowlisting Requirements

www.invicti.com
r87.me
Allowlist the following addresses according to your region:
- US region: 34.237.50.127, us-avservice.netsparkercloud.com, s3.us-east-1.amazonaws.com
- EU region: 18.193.27.197, eu-avservice.netsparker.cloud, s3.eu-central-1.amazonaws.com
- CA region: 52.60.130.46, ca-avservice.netsparker.cloud, s3.ca-central-1.amazonaws.com

Required Access

User(s) must have root privileges to run the required commands.

Step 1. Downloading authentication verifier agent

You need to download the installation files of the authentication verifier agent.

How to download the authentication verifier agent

Log in to Invicti Enterprise.
From the main menu, go to Agents > Manage Agents > Configure New Agent.
From the Authentication Verifier section, select Linux to download the required files to install the verifier agent.

Step 2. Installing authentication verifier agent

How to install the authentication verifier agent

Open a terminal window.
Update the following operating system application repositories:

sudo apt update && sudo apt upgrade -y

Install the following dependent packages:

sudo apt-get install p7zip-full
sudo apt install -y wget gss-ntlmssp nano mono-complete apt-transport-https

Next, install dotnet-sdk-3.1 for Linux operating systems. (This 4th step is only required for internal agents older than version 2.0.2.157.)

If you’ve already installed the SDK or runtime, use the dotnet –list-sdks and dotnet –list-runtimes commands to see which versions are installed.

wget https://packages.microsoft.com/config/debian/10/packages-microsoft-prod.deb -O packages-microsoft-prod.deb

sudo dpkg -i packages-microsoft-prod.deb && sudo apt update

sudo apt install -y dotnet-sdk-3.1

Create a folder for Invicti Verifier dependency:

sudo mkdir -p /home/[YOUR_USER]/.local/share/Netsparker_Ltd

sudo chown -R [YOUR_USER] /home/[YOUR_USER]/.local/share

[YOUR_USER] in the 5th step must be the same as [YOUR_USER] in the unit file described later in this article.

Install the Headless Chrome browser dependencies:

sudo apt install -y gconf-service libasound2 libatk1.0-0 libatk-bridge2.0-0 libc6 libcairo2 libcups2 libdbus-1-3 libexpat1 libfontconfig1 libgcc1 libgconf-2-4 libgdk-pixbuf2.0-0 libglib2.0-0 libgtk-3-0 libnspr4 libpango-1.0-0 libpangocairo-1.0-0 libstdc++6 libx11-6 libx11-xcb1 libxcb1 libxcomposite1 libxcursor1 libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 libxss1 libxtst6 ca-certificates fonts-liberation libappindicator1 libnss3 lsb-release xdg-utils libgdiplus

Only for Kali distributions, you may face a problem while installing the libappindicator1 dependency specified in the 6th step. If you do so, see Adding Debian Repository to the Sources.List in Kali Rolling.

Next, extract the TAR file:

To extract the authentication verifier agent, run the following commands:

cd /home/[YOUR_USER]

tar -xvf Invicti_Enterprise_Verifier_Agent.tar --one-top-level

Open appsettings.json file via any text editor you prefer in order to enter the necessary information, such as ApiToken:

cd /home/[YOUR_USER]/Invicti_Enterprise_Verifier_Agent

nano appsettings.json

These settings will be used by the agent:

AgentName: This can be anything you want. This text will be displayed when you are starting a new scan. (If you are going to install more than one instance of the agent, you must set a unique agentName value for each instance, something you will use later.)
AgentType: This can be Standard or Cloud. If you want to use Cloud Provider for scanning, AgentType must be Cloud.
ApiToken: In Invicti Enterprise, the Agent Token is displayed in the Configure New Agent window. Copy the value into the apiToken.

Changing default data folder for the authentication verifier agent

To change the default data folder, add the following attribute under AgentInfo: “ScanDataFolderPath”: “FullPath”

The full path, for example, can be the following: /home/[YOUR_USER]/[data folder]/

If you modify the existing agent’s appsettings.json file, you need to restart the service. If you add this line to the new agent, you can keep following the installation instruction.

Do not edit the ApiRootUrl address. If edited, your authentication verifier agent may not work.
Allowlist the ApiRootUrl address so that the authentication verifier agents can access the verifier server for the form authentication.
Make sure the machine where the authentication verifier agent is installed can access the ApiRootURL.

Setting proxy in authentication verifier agent

You can set a proxy for the authentication verifier agent in Invicti Enterprise. You are required to manually enter proxy settings into the appsettings.json file with your preferred text editor.

Invicti supports Basic Authentication but not Digest and NTLM.

Field	Description
Proxy Mode	Enter your proxy settings if you want the Agent to use or not to use the proxy. There are three modes: NoProxy: The Agent does not use a proxy even if you configure the server’s proxy settings. SystemProxy: The Agent uses the System Proxy that was defined on the server. CustomProxy: The Agent uses Custom Proxy that you define in the appsettings.json file.
Use Default Credentials	Enter true if you authenticate to the proxy via the user that the Agent service is defined
Username	Enter a username for authentication
Password	Enter a password for authentication
Domain	Enter a domain name
Address	Enter a proxy address. Only IP address or hostname without schema and port is allowed.
Port	Enter a port for the proxy
Bypass on Local	Enter a value that indicates whether to bypass the proxy server for local addresses.
Bypass List	Enter the address(es) that do not use the proxy server.

Using Proxy Auto-Configuration file

You can use Proxy Automatic Configuration (PAC) to configure your proxy. A PAC file lets you describe the proxy configuration in a file using JavaScript, so you can manage your proxy settings effortlessly.

To use a PAC file, you must set the Proxy Mode to System Proxy in the appsetting.json file.

How to use a Proxy Auto-Configuration file on Linux (Debian Distribution)

Go to Settings > Network > Network Proxy.
From the Network Proxy window, select Automatic.
In the Configuration URL field, enter the PAC file’s URL address.

Close the window.

How to Add Debian Repository to the Source.List in the Kali Rolling Distribution

You need to add the Debian Repository to the Source.List in Kali Rolling so that you can install the libappindicator1 for the Headless Chrome browser dependencies.

Open a terminal window.
```
sudo nano /etc/apt/sources.list
```
Add the following lines to the Source.List file

deb http://deb.debian.org/debian buster main contrib non-free
deb-src http://deb.debian.org/debian buster main contrib non-free

Save and close the document.
```
sudo apt update
```
```
sudo apt install libappindicator1
```

Once you install the libappindicator1, you can resume Installing the Authentication Verifier Agent with the 7th step.

Step 3. Setting authentication verifier agent as a Linux Service

An authentication verifier agent should be configured as a Linux service so that it can poll the Invicti Enterprise servers regularly and can take the scan initiation command from the server.

You can complete this process in three steps:

Add a unit file for an Invicti Agent

Open a terminal
```
cd /etc/systemd/system
```
```
sudo touch [YOUR_AGENT_NAME].service
```
```
sudo nano [YOUR_AGENT_NAME].service
```

The AgentName in the appsetting.json file and the unit file name for the agent must have the same name.

Add the following script into [YOUR_AGENT_NAME].service

For internal agents older than 2.0.2.157, use the following script:

[Unit]
Description=netsparker.service description
[Service]
Type=notify
KillMode=process
Restart=always
RestartSec=30
SyslogIdentifier=[YOUR_USER]
KillSignal=SIGINT
User=[YOUR_USER]
WorkingDirectory= [YOUR_AGENT_DIRECTORY_PATH]
ExecStart=/usr/bin/dotnet [YOUR_AGENT_DIRECTORY_PATH]/Netsparker.Cloud.Agent.dll
[Install]
WantedBy=multi-user.target

For internal agents version 2.0.2.157 or newer, use the following script:

[Unit]
Description=netsparker.service description
[Service]
Type=notify
KillMode=process
Restart=always
RestartSec=30
SyslogIdentifier=[YOUR_USER]
KillSignal=SIGINT
User=[YOUR_USER]
WorkingDirectory= [YOUR_AGENT_DIRECTORY_PATH]
ExecStart = [Your Agent Directory path]/Netsparker.Cloud.Agent
[Install]
WantedBy=multi-user.target

The [YOUR_USER] in the unit file must be the same as [YOUR_USER] that you entered while installing the verifier agent.

Save and close the document.

Configure Sudoers for an Invicti Agent

```
sudo cd /etc/sudoers.d
```
```
sudo touch [YOUR_AGENT_NAME]-systemctl
```

sudo visudo -f [YOUR_AGENT_NAME]-systemctl

Add the following script into [YOUR_AGENT_NAME]-systemctl

[YOUR_USER] ALL=(ALL:ALL) NOPASSWD: /usr/bin/systemctl start [YOUR_AGENT_NAME].service

[YOUR_USER] ALL=(ALL:ALL) NOPASSWD: /usr/bin/systemctl stop [YOUR_AGENT_NAME].service

Save and close the document.

Start Invicti Enterprise Agent as a Linux Service

```
sudo systemctl daemon-reload
```

sudo systemctl start [YOUR_AGENT_NAME].service

You can now check the status of the connection between Invicti Enterprise and the authentication verifier agent. From the Agents menu, select Manage Verifier.

To keep the scanning agent service running in case of rebooting of the machine where the Agent is installed, do the following:

Open a terminal.

Run the following code: sudo systemctl enable [YOUR_AGENT_NAME].service

Updating authentication verifier agents

There are three methods to update your authentication verifier agent.

When a new verifier agent version has been published, you can update your Agents manually using installation files on the machines on which agents are installed.
You can update agents manually by selecting Update Agent (visible only when the Enable Auto Update is not configured and the new version of the Agent is available). While the update is in progress, the State field will display ‘Updating’.
You can enable the auto update feature. The target verifier agent updates itself as soon as possible when it’s idle.

How to enable automatic Authentication Verifier Agent updates

From the main menu, select Agents > Manage Verifiers.
Next to the relevant agent, select the Command drop-down, then Enable Auto Update.

Installing multiple authentication verifier agents on Linux

You can install more than one agent in Linux.

Make sure that you enter a different name for the new agent.

How to install multiple agents on Linux

Open a terminal window.
Create a new folder for the new agent.
Copy the TAR file into the new folder and extract the TAR file
Follow the instructions in Step 2. Installing authentication verifier agentand Step 3. Setting authentication verifier agent as a Linux Service.

Uninstalling the authentication verifier agent

You may uninstall verifier agents.

How to uninstall the authentication verifier agent

Open a terminal window.

sudo systemctl stop {your-agent-name}.service

```
cd /etc/systemd/system
```
```
sudo rm {your-agent-name}.service
```
```
systemctl daemon-reload
```

This command will stop and delete the verifier agent service. If required, you can delete the related folder.