4 files changed, 224 insertions, 0 deletions
diff --git a/roles/harden/handlers/main.yaml b/roles/harden/handlers/main.yaml
new file mode 100644
index 0000000..e25c78f
--- /dev/null
+++ b/roles/harden/handlers/main.yaml
@@ -0,0 +1,38 @@
+- name: update grub
+  command: update-grub
+
+- name: reload fail2ban
+  command: fail2ban-client reload
+
+- name: enable ufw
+  ufw:
+    state: enabled
+    policy: deny
+
+- name: restart ufw
+  systemd:
+    name: ufw
+    state: restarted
+    enabled: true
+  when: ansible_facts['service_mgr'] == 'systemd'
+
+- name: restart ssh
+  systemd:
+    name: ssh
+    state: restarted
+    enabled: true
+  when: ansible_facts['service_mgr'] == 'systemd'
+
+- name: restart unattended-upgrades
+  systemd:
+    name: unattended-upgrades
+    state: restarted
+    enabled: true
+  when: ansible_facts['service_mgr'] == 'systemd'
+
+- name: restart fail2ban
+  systemd:
+    name: fail2ban
+    state: restarted
+    enabled: true
+  when: ansible_facts['service_mgr'] == 'systemd'
diff --git a/roles/harden/tasks/harden.yaml b/roles/harden/tasks/harden.yaml
new file mode 100644
index 0000000..cf60e95
--- /dev/null
+++ b/roles/harden/tasks/harden.yaml
@@ -0,0 +1,139 @@
+- name: remove snap and snapd
+  apt:
+    name:
+      - snap
+      - snapd
+    state: absent
+    purge: true
+
+- name: clean apt cache
+  apt:
+    autoclean: yes
+
+- name: clear /etc/issue and /etc/motd
+  copy:
+    content: ""
+    dest: "{{ item }}"
+  loop:
+    - /etc/issue
+    - /etc/motd
+
+- name: check if /etc/update-motd.d directory exists
+  stat:
+    path: /etc/update-motd.d
+  register: motd_dir
+
+- name: find files in /etc/update-motd.d
+  find:
+    paths: /etc/update-motd.d
+    file_type: file
+  register: motd_files
+  when: motd_dir.stat.exists
+
+- name: remove execute permissions from all files in /etc/update-motd.d
+  file:
+    path: "{{ item.path }}"
+    mode: u-x,g-x,o-x
+  loop: "{{ motd_files.files }}"
+  when: motd_dir.stat.exists
+
+- name: enforce root-only cron/at
+  file:
+    path: "{{ item }}"
+    state: touch
+    owner: root
+    group: root
+    mode: '0600'
+  loop:
+    - /etc/cron.allow
+    - /etc/at.allow
+
+- name: remove deny files for cron and at
+  file:
+    path: "{{ item }}"
+    state: absent
+  loop:
+    - /etc/cron.deny
+    - /etc/at.deny
+
+- name: backup sshd_config
+  copy:
+    src: /etc/ssh/sshd_config
+    dest: "/etc/ssh/sshd_config.bak_{{ ansible_date_time.iso8601_basic }}"
+    remote_src: yes
+
+- name: harden sshd_config
+  copy:
+    dest: /etc/ssh/sshd_config
+    content: |
+      Port 22
+      Banner /etc/issue
+      UsePAM yes
+      Protocol 2
+      Subsystem sftp /usr/lib/openssh/sftp-server
+      LogLevel verbose
+      PrintMotd no
+      AcceptEnv LANG LC_*
+      MaxSessions 5
+      StrictModes yes
+      Compression no
+      MaxAuthTries 3
+      IgnoreRhosts yes
+      PrintLastLog yes
+      AddressFamily inet
+      X11Forwarding no
+      PermitRootLogin yes
+      AllowTcpForwarding no
+      ClientAliveInterval 1200
+      AllowAgentForwarding no
+      PermitEmptyPasswords no
+      ClientAliveCountMax 0
+      GSSAPIAuthentication no
+      KerberosAuthentication no
+      IgnoreUserKnownHosts yes
+      PermitUserEnvironment no
+      ChallengeResponseAuthentication no
+      MACs hmac-sha2-512,hmac-sha2-256
+      Ciphers aes128-ctr,aes192-ctr,aes256-ctr
+
+- name: regenerate SSH host keys
+  shell: |
+    rm -f /etc/ssh/ssh_host_*key*
+    ssh-keygen -t ed25519 -f /etc/ssh/ssh_host_ed25519_key -N ""
+    ssh-keygen -t rsa -b 4096 -f /etc/ssh/ssh_host_rsa_key -N ""
+  args:
+    creates: /etc/ssh/ssh_host_ed25519_key
+  notify: restart ssh
+
+- name: enable unattended-upgrades
+  shell: dpkg-reconfigure --priority=low unattended-upgrades
+  args:
+    creates: /etc/apt/apt.conf.d/50unattended-upgrades
+  notify: restart unattended-upgrades
+
+- name: disable ipv6 in grub
+  lineinfile:
+    path: /etc/default/grub
+    regexp: '^GRUB_CMDLINE_LINUX='
+    line: 'GRUB_CMDLINE_LINUX="ipv6.disable=1"'
+  notify: update grub
+
+- name: allow ssh port and enable ufw
+  ufw:
+    rule: allow
+    port: 22
+    proto: tcp
+  notify:
+    - enable ufw
+    - restart ufw
+
+- name: deploy custom fail2ban jail.local
+  template:
+    src: templates/jail.local.j2
+    dest: /etc/fail2ban/jail.local
+    owner: root
+    group: root
+    mode: '0644'
+  notify:
+    - restart fail2ban
+    - reload fail2ban
diff --git a/roles/harden/tasks/main.yaml b/roles/harden/tasks/main.yaml
new file mode 100644
index 0000000..95fdd29
--- /dev/null
+++ b/roles/harden/tasks/main.yaml
@@ -0,0 +1 @@
+- import_tasks: tasks/harden.yaml
diff --git a/roles/harden/templates/jail.local.j2 b/roles/harden/templates/jail.local.j2
new file mode 100644
index 0000000..dd548df
--- /dev/null
+++ b/roles/harden/templates/jail.local.j2
@@ -0,0 +1,46 @@
+[INCLUDES]
+#before = paths-distro.conf
+before = paths-debian.conf
+
+[DEFAULT]
+#ignoreself = true
+#ignoreip = 127.0.0.1/8 ::1
+ignorecommand =
+bantime  = 1h
+findtime  = 10m
+maxretry = 3
+maxmatches = %(maxretry)s
+backend = auto
+usedns = warn
+logencoding = auto
+enabled = false
+mode = normal
+filter = %(__name__)s[mode=%(mode)s]
+destemail = root@localhost
+sender = root@<fq-hostname>
+mta = sendmail
+protocol = tcp
+chain = <known/chain>
+port = 0:65535
+fail2ban_agent = Fail2Ban/%(fail2ban_version)s
+banaction = iptables-multiport
+banaction_allports = iptables-allports
+action_ = %(banaction)s[port="%(port)s", protocol="%(protocol)s", chain="%(chain)s"]
+action_mw = %(action_)s
+            %(mta)s-whois[sender="%(sender)s", dest="%(destemail)s", protocol="%(protocol)s", chain="%(chain)s"]
+action_mwl = %(action_)s
+             %(mta)s-whois-lines[sender="%(sender)s", dest="%(destemail)s", logpath="%(logpath)s", chain="%(chain)s"]
+action_xarf = %(action_)s
+             xarf-login-attack[service=%(__name__)s, sender="%(sender)s", logpath="%(logpath)s", port="%(port)s"]
+action_cf_mwl = cloudflare[cfuser="%(cfemail)s", cftoken="%(cfapikey)s"]
+                %(mta)s-whois-lines[sender="%(sender)s", dest="%(destemail)s", logpath="%(logpath)s", chain="%(chain)s"]
+action_blocklist_de  = blocklist_de[email="%(sender)s", service="%(__name__)s", apikey="%(blocklist_de_apikey)s", agent="%(fail2ban_agent)s"]
+action_abuseipdb = abuseipdb
+action = %(action_)s
+
+[sshd]
+mode = aggressive
+enabled = true
+port = ssh
+logpath = %(sshd_log)s
+backend = %(sshd_backend)s