# SPDX-Version: 3.0
# SPDX-CreationInfo: 2025-05-05; WEIDNER, Marc S.; <cendev@coresecret.eu>
# SPDX-ExternalRef: GIT https://cendev.eu/marc.weidner/CISS.2025.debian.live.builder.git
# SPDX-FileContributor: WEIDNER, Marc S.; Centurion Intelligence Consulting Agency
# SPDX-FileCopyrightText: 2024–2025; WEIDNER, Marc S.; <cendev@coresecret.eu>
# SPDX-FileType: SOURCE
# SPDX-License-Identifier: EUPL-1.2 OR LicenseRef-CCLA-1.0
# SPDX-LicenseComment: This file is part of the CISS.2025.hardened.installer framework.
# SPDX-PackageName: CISS.2025.debian.live.builder
# SPDX-Security-Contact: security@coresecret.eu

Include /etc/ssh/sshd_config.d/*.conf

Protocol 2

Banner /etc/banner
DebianBanner no
VersionAddendum none

Compression no
LogLevel VERBOSE

AddressFamily any
ListenAddress 0.0.0.0
ListenAddress ::
Port MUST_BE_CHANGED
AllowUsers root
UseDNS no
RekeyLimit 1G 1h

HostKey /etc/ssh/ssh_host_ed25519_key
HostKey /etc/ssh/ssh_host_rsa_key

PubkeyAuthentication yes
PermitRootLogin prohibit-password
PasswordAuthentication no
PermitEmptyPasswords no
StrictModes yes
LoginGraceTime 2m
MaxAuthTries 3
MaxSessions 2
MaxStartups 10:30:60
ClientAliveInterval 300
ClientAliveCountMax 2

AuthorizedKeysFile %h/.ssh/authorized_keys

AllowAgentForwarding no
AllowTcpForwarding no
X11Forwarding no
GatewayPorts no

# ssh -Q cipher | cipher-auth | compression | kex | kex-gss | key | key-cert | key-plain | key-sig | mac | protocol-version | sig
Ciphers aes256-gcm@openssh.com
KexAlgorithms sntrup761x25519-sha512@openssh.com,curve25519-sha256@libssh.org,curve25519-sha256,diffie-hellman-group18-sha512,diffie-hellman-group16-sha512
HostKeyAlgorithms rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-ed25519
MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com
CASignatureAlgorithms rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp384,ssh-ed25519,sk-ssh-ed25519@openssh.com

# Change to yes to enable challenge-response passwords (beware issues with some PAM modules and threads)
KbdInteractiveAuthentication no

# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication.  Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes

# Allow client to pass locale environment variables
AcceptEnv LANG LC_*

# override default of no subsystems
Subsystem sftp /usr/lib/openssh/sftp-server

PidFile /var/run/sshd.pid
PrintMotd no
PrintLastLog yes
TCPKeepAlive no

# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts!
# Change to yes if you don't trust ~/.ssh/known_hosts for HostbasedAuthentication!
HostbasedAuthentication no

# Don't read the user's ~/.rhosts and ~/.shosts files
# IgnoreRhosts yes

# UsePrivilegeSeparation yes

# Kerberos options
# KerberosAuthentication no
# KerberosOrLocalPasswd yes
# KerberosTicketCleanup yes
# KerberosGetAFSToken no

# GSSAPI options
# GSSAPIAuthentication no
# GSSAPICleanupCredentials yes
# GSSAPIStrictAcceptorCheck yes
# GSSAPIKeyExchange no

# AuthorizedPrincipalsFile none
# AuthorizedKeysCommand none
# AuthorizedKeysCommandUser nobody

# PermitTunnel no
# ChrootDirectory none
# X11DisplayOffset 10
# X11UseLocalhost yes
# PermitTTY yes
# PermitUserEnvironment no
# IgnoreUserKnownHosts no

# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=sh