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Installing Authentication Verifier Agent on Linux (RedHat 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.
  • If the website that you scan requires a form authentication, you can download and configure an internal verifier agent. This internal agent performs the authentication so that you can run authenticated scanning in your network.

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 (RedHat). Using Windows? See Installing Authentication Verifier Agents. For the Debian distributions, see Installing Authentication Verifier Agent on Linux (Debian 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, and CyberArk Vault and HashiCorp Vault

Downloading and configuring authentication verifier agent

There are 3 steps in this process:

  1. Downloading an authentication verifier agent
  2. Installing an authentication verifier agent
  3. Setting an authentication verifier agent as a Linux Service

This instruction is valid for the authentication verifier agents 2.0.2.134 or newer versions. If you have older versions, it is strongly recommended that you delete the older versions and reinstall the newer verifier agents.

Prerequisites

Software Requirements

  • .NET Core 3.1

Hardware Requirements

  • 1.4 GHz Processor (2.0 GHz or faster recommended)
  • 2 GB RAM (4 GB 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 Service 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
    • EU region: 18.193.27.197, eu-avservice.netsparker.cloud
    • CA region: 52.60.130.46, ca-avservice.netsparker.cloud

Required Access

  • User(s) must have administrator 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
  1. Log in to Invicti Enterprise.
  2. From the main menu, go to Agents > Manage Agents > Configure New Agent.
  3. From the Authentication Verifier section, select Linux to download the required files to install the verifier agent.

Step 2. Installing authentication verifier agent

Once you download the required file, you can install a Invicti Enterprise scanning agent in your environment.

How to Install a Invicti Enterprise Agent
  1. Open a terminal window.
  2. Install the dependent packages (Ignore this step for Fedora distribution):
sudo yum install -y epel-release
  1. Update operating system application repositories:
sudo yum update -y
  1. Install the dependent packages:
sudo yum install p7zip p7zip-plugins
sudo yum install -y nano tar gssntlmssp mono-complete libgdiplus
  1. Next, install .NET Core 3.1 SDK for Linux OS:

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.

CentOS 8, Fedora 32, Fedora 33:

sudo yum install -y dotnet-sdk-3.1

CentOS 7:

sudo rpm -Uvh https://packages.microsoft.com/config/centos/7/packages-microsoft-prod.rpm
sudo yum install -y dotnet-sdk-3.1
  1. Create folder for Invicti Verifier dependency:
sudo mkdir -p /home/[YOUR_USER]/.local/share/Invicti_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.

  1. Install the Headless Chrome browser dependencies:
sudo yum install -y pango.x86_64 libXcomposite.x86_64 libXcursor.x86_64 libXdamage.x86_64 libXext.x86_64 libXi.x86_64 libXtst.x86_64 cups-libs.x86_64 libXScrnSaver.x86_64 libXrandr.x86_64 GConf2.x86_64 alsa-lib.x86_64 atk.x86_64 gtk3.x86_64 xorg-x11-fonts-100dpi xorg-x11-fonts-75dpi xorg-x11-utils xorg-x11-fonts-cyrillic libX11-xcb.so.1 libnss3.so xorg-x11-fonts-Type1 xorg-x11-fonts-misc 
  1. Next, extract the TAR file:
  • To extract the authentication verifier agent, run the following commands:
tar xf Invicti_Enterprise_Verifier_Agent.tar

Open appsettings.json file via any text editor you prefer, for example:

sudo nano appsettings.json

These settings will be used by the authentication verifier 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.
  • ApiToken: In Invicti Enterprise, the Agent Token is displayed in the Configure New Agent window. Copy the value into the apiToken.
  • Do not edit the ApiRootUrl address. If edited, your authentication verifier agent may not work.
  • Whitelist 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 to 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  in Linux (Debian Distribution)
  1. Go to Settings > Network > Network Proxy.
  2. From the Network Proxy window, select Automatic.
  3. In the Configuration URL field, enter the PAC file’s URL address.

  1. Close the window.

Step 3. Setting authentication verifier agent as a Linux Service

When you install an internal authentication verifier agent, you need to set it as a Linux service. So, the verifier agent can poll the Invicti Enterprise servers regularly and can take the initiation command from the server.

You can complete this process in three steps:

Add a unit file for a Invicti Agent

  1. Open a terminal
  2. cd /etc/systemd/system
  3. sudo touch [YOUR_AGENT_NAME].service
  4. 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.

  1. Add the following script into [YOUR_AGENT_NAME].service
[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

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

  1. sudo cd /etc/sudoers.d
  2. sudo touch [YOUR_AGENT_NAME]-systemctl
  3. sudo visudo -f [YOUR_AGENT_NAME]-systemctl
  4. 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

  1. sudo systemctl daemon-reload
  2. 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 Verifiers.

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
  1. From the main menu, select Agents > Manage Verifiers.
  2. 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 the Same Operating System
  1. Open a terminal window.
  2. Create a new folder for the new agent.
  3. Copy the TAR file into the new folder, and extract the TAR file
  4. Follow the instructions in Step 2. Installing authentication verifier agent and 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
  1. Open a terminal window.
  2. sudo systemctl stop {your-agent-name}.service
  3. cd /etc/systemd/system
  4. sudo rm {your-agent-name}.service
  5. systemctl daemon-reload

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

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