50 lines
2.1 KiB
Bash
50 lines
2.1 KiB
Bash
#!/bin/bash
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# This script is designed to configure the SSH server on a Linux system according to Mozilla's security best practices.
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# Its main purpose is to enhance the security of SSH connections by enforcing modern encryption standards, disabling insecure protocols, and reducing potential attack vectors.
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# The script backs up the original SSH configuration file, applies a new set of secure settings, and then restarts the SSH service to apply the changes.
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# These settings include disabling password authentication, limiting access to strong ciphers and key exchange methods, and enhancing brute-force protection.
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# These recommendations are based on Mozilla's guidelines, which can be found here: https://infosec.mozilla.org/guidelines/openssh
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# Usage:
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# To run this script, save it as "secure_ssh.sh" and make it executable by running the command: `chmod +x secure_ssh.sh`.
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# After that, execute it with root privileges using: `sudo ./secure_ssh.sh`.
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# The script will automatically apply the recommended configuration changes and restart the SSH service.
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# Variables
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SSHD_CONFIG="/etc/ssh/sshd_config"
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# Backup the old configuration
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cp "$SSHD_CONFIG" "${SSHD_CONFIG}.bak"
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# Modify the sshd_config file
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cat <<EOL > "$SSHD_CONFIG"
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# Mozilla SSH Security Recommendations
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Protocol 2
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# Enable only secure ciphers
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Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
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# Enable only secure key exchange algorithms
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KexAlgorithms curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
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# Enable only secure MAC algorithms
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MACs hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha2-512
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# Disable password authentication for stronger security
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PasswordAuthentication no
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# Disable old host keys
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HostKey /etc/ssh/ssh_host_ed25519_key
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HostKey /etc/ssh/ssh_host_rsa_key
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# Restrict root access
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PermitRootLogin no
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# Strict connection policy
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MaxAuthTries 3
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LoginGraceTime 30
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EOL
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# Restart the SSH service
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systemctl restart sshd
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echo "SSH configuration has been updated according to Mozilla's security recommendations."
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