.

security/hardening/linux-hardening/assets/ssh-hardening.conf

@@ -0,0 +1,111 @@
+# SSH Server Hardening Configuration
+# Place in /etc/ssh/sshd_config.d/hardening.conf
+# Restart SSH: systemctl restart sshd
+
+#------------------------------------------------------------------------------
+# AUTHENTICATION
+#------------------------------------------------------------------------------
+
+# Disable root login
+PermitRootLogin no
+
+# Disable password authentication
+PasswordAuthentication no
+
+# Enable public key authentication
+PubkeyAuthentication yes
+
+# Disable empty passwords
+PermitEmptyPasswords no
+
+# Disable keyboard-interactive authentication
+KbdInteractiveAuthentication no
+
+# Disable challenge-response authentication
+ChallengeResponseAuthentication no
+
+# Maximum authentication attempts
+MaxAuthTries 3
+
+# Maximum sessions per connection
+MaxSessions 2
+
+# Maximum simultaneous unauthenticated connections
+MaxStartups 10:30:60
+
+# Login grace time
+LoginGraceTime 60
+
+#------------------------------------------------------------------------------
+# SESSION
+#------------------------------------------------------------------------------
+
+# Client alive settings (timeout)
+ClientAliveInterval 300
+ClientAliveCountMax 2
+
+# Disable TCP forwarding
+AllowTcpForwarding no
+
+# Disable agent forwarding
+AllowAgentForwarding no
+
+# Disable stream local forwarding
+AllowStreamLocalForwarding no
+
+# Disable X11 forwarding
+X11Forwarding no
+
+# Disable user environment processing
+PermitUserEnvironment no
+
+# Disable tunnel device forwarding
+PermitTunnel no
+
+# Disable gateway ports
+GatewayPorts no
+
+#------------------------------------------------------------------------------
+# CRYPTOGRAPHY
+#------------------------------------------------------------------------------
+
+# Protocol version (SSH-2 only)
+Protocol 2
+
+# Strong ciphers only
+Ciphers aes256-gcm@openssh.com,chacha20-poly1305@openssh.com,aes256-ctr
+
+# Strong MACs only
+MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256
+
+# Strong key exchange algorithms
+KexAlgorithms curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512
+
+# Strong host key algorithms
+HostKeyAlgorithms ssh-ed25519,rsa-sha2-512,rsa-sha2-256
+
+#------------------------------------------------------------------------------
+# LOGGING
+#------------------------------------------------------------------------------
+
+# Log level
+LogLevel VERBOSE
+
+# Enable sftp logging
+Subsystem sftp /usr/lib/openssh/sftp-server -l INFO
+
+#------------------------------------------------------------------------------
+# ACCESS CONTROL
+#------------------------------------------------------------------------------
+
+# Use PAM
+UsePAM yes
+
+# Show banner
+Banner /etc/issue.net
+
+# Restrict to specific users (uncomment and customize)
+# AllowUsers admin deploy
+
+# Restrict to specific groups (uncomment and customize)
+# AllowGroups sshusers admins

security/hardening/linux-hardening/assets/sysctl-hardening.conf

@@ -0,0 +1,104 @@
+# Linux Kernel Security Hardening
+# Place in /etc/sysctl.d/99-security.conf
+# Apply with: sysctl -p /etc/sysctl.d/99-security.conf
+
+#------------------------------------------------------------------------------
+# NETWORK SECURITY
+#------------------------------------------------------------------------------
+
+# Disable IP forwarding (unless router)
+net.ipv4.ip_forward = 0
+net.ipv6.conf.all.forwarding = 0
+
+# Disable packet redirect sending
+net.ipv4.conf.all.send_redirects = 0
+net.ipv4.conf.default.send_redirects = 0
+
+# Disable ICMP redirect acceptance
+net.ipv4.conf.all.accept_redirects = 0
+net.ipv4.conf.default.accept_redirects = 0
+net.ipv4.conf.all.secure_redirects = 0
+net.ipv4.conf.default.secure_redirects = 0
+net.ipv6.conf.all.accept_redirects = 0
+net.ipv6.conf.default.accept_redirects = 0
+
+# Disable source routing
+net.ipv4.conf.all.accept_source_route = 0
+net.ipv4.conf.default.accept_source_route = 0
+net.ipv6.conf.all.accept_source_route = 0
+net.ipv6.conf.default.accept_source_route = 0
+
+# Log suspicious packets
+net.ipv4.conf.all.log_martians = 1
+net.ipv4.conf.default.log_martians = 1
+
+# Ignore ICMP broadcast requests
+net.ipv4.icmp_echo_ignore_broadcasts = 1
+
+# Ignore bogus ICMP error responses
+net.ipv4.icmp_ignore_bogus_error_responses = 1
+
+# Enable reverse path filtering (spoofing protection)
+net.ipv4.conf.all.rp_filter = 1
+net.ipv4.conf.default.rp_filter = 1
+
+# Enable TCP SYN cookies (SYN flood protection)
+net.ipv4.tcp_syncookies = 1
+
+# Disable IPv6 router advertisements
+net.ipv6.conf.all.accept_ra = 0
+net.ipv6.conf.default.accept_ra = 0
+
+# Disable IPv6 if not needed
+# net.ipv6.conf.all.disable_ipv6 = 1
+# net.ipv6.conf.default.disable_ipv6 = 1
+
+#------------------------------------------------------------------------------
+# KERNEL SECURITY
+#------------------------------------------------------------------------------
+
+# Enable ASLR
+kernel.randomize_va_space = 2
+
+# Restrict access to kernel pointers
+kernel.kptr_restrict = 2
+
+# Restrict dmesg access
+kernel.dmesg_restrict = 1
+
+# Restrict ptrace scope
+kernel.yama.ptrace_scope = 1
+
+# Disable magic SysRq key
+kernel.sysrq = 0
+
+# Restrict unprivileged user namespaces
+# kernel.unprivileged_userns_clone = 0
+
+# Restrict loading TTY line disciplines
+dev.tty.ldisc_autoload = 0
+
+# Restrict userfaultfd to privileged users
+vm.unprivileged_userfaultfd = 0
+
+# Restrict BPF
+kernel.unprivileged_bpf_disabled = 1
+net.core.bpf_jit_harden = 2
+
+# Restrict perf events
+kernel.perf_event_paranoid = 3
+
+#------------------------------------------------------------------------------
+# FILE SYSTEM SECURITY
+#------------------------------------------------------------------------------
+
+# Restrict core dumps
+fs.suid_dumpable = 0
+
+# Restrict hardlinks and symlinks
+fs.protected_hardlinks = 1
+fs.protected_symlinks = 1
+
+# Protect FIFOs and regular files
+fs.protected_fifos = 2
+fs.protected_regular = 2