ssh-scan: SSH Server Security Scanner

Overview

ssh-scan connects to a specified SSH server to collect and analyze various security-related information. This allows for an assessment of the server's security posture and identification of non-recommended configurations or vulnerable algorithm usage.

Key Features

The core features provided by ssh-scan are as follows:

Analysis of supported encryption algorithms (Ciphers)
Checking key exchange methods (Key Exchange Algorithms)
Information retrieval of host keys (Host Key Algorithms)
Identification of potential vulnerabilities and provision of recommendations

Key Options

Here are the main options useful when using the ssh-scan command.

Target Specification

Output Format

Information Display

Generated command:

Try combining the commands.

Description:

`ssh-scan` Executes the command.

Combine the above options to virtually execute commands with AI.

Usage Examples

Practical usage examples of the ssh-scan command.

Basic SSH Server Scan

ssh-scan --target example.com

Scans the SSH server of a specified host with default settings.

Scan SSH Server on a Specific Port

ssh-scan --target example.com --port 2222

Scans an SSH server running on a port other than the default (22), such as 2222.

Save Results in JSON Format

ssh-scan --target example.com --format json --output scan_results.json

Saves the scan results in JSON format to a file, making it easier to integrate with other tools or for analysis.

Display Detailed Information and Host Key Fingerprint

ssh-scan --target example.com --verbose --fingerprint

Outputs the scan progress in detail and also displays the host key fingerprint information.

Installation

ssh-scan is not included by default in most Linux distributions, so it is common to install it using Python's pip package manager.

Check Python and pip Installation

Before installing ssh-scan, verify that Python 3 and pip are installed on your system. If not, you need to install them first.

python3 --version
pip3 --version

Install ssh-scan

Install the ssh-scan package using pip.

pip3 install ssh-scan

Verify Installation

After installation is complete, check if the command runs correctly.

ssh-scan --version

Tips & Precautions

Tips and precautions for effectively using ssh-scan to enhance SSH server security and reduce potential risks.

Importance of Regular Scanning

Regularly run ssh-scan whenever SSH server settings are changed or new security vulnerabilities are announced to keep your server's security status up-to-date.

Always run ssh-scan after changing SSH server settings to check the impact of the changes on security.
Scan your server regularly to quickly respond to newly discovered vulnerabilities or configuration changes.

Recommendations Based on Scan Results

General solutions for issues found in ssh-scan results.

Remove Weak Encryption Algorithms: If weak or no longer recommended encryption algorithms (e.g., 3DES, RC4) are found in the ssh-scan results, disable them in the `/etc/ssh/sshd_config` file or replace them with stronger algorithms.
Use Latest SSH Protocol: SSHv1 has many security vulnerabilities, so it must be configured to use SSHv2. Check if `Protocol 2` is set in the `sshd_config` file.
Disable Unnecessary Authentication Methods: Using key-based authentication instead of password authentication is more secure. Disable unnecessary authentication methods to reduce the attack surface.