Ubuntu 24.04: Implement 5.3.3.2.5 Ensure password maximum sequential characters is configured

components/pam.yml

@@ -51,6 +51,7 @@ rules:
 - accounts_password_pam_lcredit
 - accounts_password_pam_maxclassrepeat
 - accounts_password_pam_maxrepeat
+- accounts_password_pam_maxsequence
 - accounts_password_pam_minclass
 - accounts_password_pam_minlen
 - accounts_password_pam_ocredit

controls/cis_ubuntu2404.yml

@@ -1962,8 +1962,9 @@ controls:
     levels:
       - l1_server
       - l1_workstation
-    status: planned
-    notes: TODO. Rule does not seem to be implemented, nor does it map to any rules in ubuntu2204 profile.
+    rules:
+      - accounts_password_pam_maxsequence
+    status: automated
 
   - id: 5.3.3.2.6
     title: Ensure password dictionary check is enabled (Automated)

linux_os/guide/system/accounts/accounts-pam/password_quality/password_quality_pwquality/accounts_password_pam_maxsequence/rule.yml

@@ -0,0 +1,32 @@
+documentation_complete: true
+
+
+title: 'Limit the maximum number of sequential characters in passwords'
+
+description: |-
+    The <tt>pwquality maxsequence</tt> setting defines the maximum allowable length for consecutive 
+    character sequences in a new password. Such sequences can be, e.g., 123 or abc. If the value is 
+    set to 0, this check will be turned off.
+    <br /><br />
+    Note: Passwords that consist mainly of such sequences are unlikely to meet the simplicity criteria 
+    unless the sequence constitutes only a small portion of the overall password.
+
+rationale: |-
+    Use of a strong password helps to increase the time and resources required to
+    compromise the password. Password complexity, or strength, is a measure of the
+    effectiveness of a password in resisting attempts at guessing and brute-force attacks.
+    <br /><br />
+    Password complexity is one important factor that determines the duration required to crack it.
+    A more intricate password results in a larger number of potential combinations that must be 
+    tested before successfully compromising the password.
+
+severity: medium
+
+platform: package[pam]
+
+template:
+    name: accounts_password
+    vars:
+        variable: maxsequence
+        operation: less than or equal
+        zero_comparison_operation: greater than

linux_os/guide/system/accounts/accounts-pam/password_quality/password_quality_pwquality/var_password_pam_maxsequence.var

@@ -0,0 +1,17 @@
+documentation_complete: true
+
+title: maxsequence
+
+description: 'Maximum Number of Consecutive Character Sequences in a Password'
+
+type: number
+
+operator: equals
+
+interactive: false
+
+options:
+    1: 1
+    2: 2
+    3: 3
+    default: 3

shared/macros/10-ansible.jinja

@@ -847,6 +847,23 @@ The following macro remediates Audit syscall rule in :code:`/etc/audit/audit.rul
     {{%- endif %}}
 {{%- endmacro %}}
 
+{{#
+    Macro used to apply changes on pam-auth-update profiles. If the "profile_name" parameter is not defined, the
+    pam-auth-update will apply all profile changes by default.
+
+:param profile_name:        Changes the default profile used by pam-auth-update.
+:type profile_name: str
+
+#}}
+{{% macro ansible_apply_pam_auth_update_changes(profile_name='') -%}}
+- name: '{{{ rule_title }}} - Ensure pam-auth-update profile changes are applied'
+  ansible.builtin.command:
+    {{%- if profile_name == '' %}}
+    cmd: pam-auth-update
+    {{%- else %}}
+    cmd: pam-auth-update --enable {{{ profile_name }}}
+    {{%- endif %}}
+{{%- endmacro %}}
 
 {{#
     Disable authselect feature if the authselect current profile is intact or inform that its
@@ -922,6 +939,17 @@ The following macro remediates Audit syscall rule in :code:`/etc/audit/audit.rul
   register: result_authselect_present
 {{%- endmacro -%}}
 
+{{#
+    Used to identify if pam-auth-update is present or not in the system.
+    Some macros can change the remediation behavior based on the presence of authselect.
+
+#}}
+{{%- macro ansible_check_pam_auth_update_presence() -%}}
+- name: '{{{ rule_title }}} - Check if system relies on pam-auth-update tool'
+  ansible.builtin.stat:
+    path: /usr/sbin/pam-auth-update
+  register: result_pam_auth_update_present
+{{%- endmacro -%}}
 
 {{#
     Ensure pam_lastlog.so PAM module shows the failed logins according to the system capabilities.
@@ -1252,6 +1280,46 @@ The following macro remediates Audit syscall rule in :code:`/etc/audit/audit.rul
     - not result_faillock_conf_check.stat.exists
 {{%- endmacro -%}}
 
+{{#
+  This macro ensures the pam_pwquality.so PAM module is enabled.
+  It is enabled using the pam-auth-update tool.
+
+:param path: The path of pam-auth-update configuration for pam_pwquality.so.
+:type parameter: str
+
+#}}
+{{%- macro ansible_pam_pwquality_enable(path) -%}}
+
+{{{ ansible_check_pam_auth_update_presence() }}}
+
+- name: {{{ rule_title }}} - Remediation where pam-auth-update tool is present
+  block:
+    - name: Check if {{{ path }}} exists
+      stat:
+        path: {{{ path }}}
+      register: pwquality_file_stat
+
+    - name: Put the content into {{{ path }}} if it does not exist
+      copy:
+        dest: {{{ path }}}
+        content: |+
+          Name: Pwquality password strength checking
+          Default: yes
+          Priority: 1024
+          Conflicts: cracklib
+          Password-Type: Primary
+          Password:
+            requisite           pam_pwquality.so retry=3
+        force: yes
+      when: not pwquality_file_stat.stat.exists
+
+    {{{ ansible_apply_pam_auth_update_changes('cac_pwquality') | indent(4) }}}
+
+  when:
+    - result_pam_auth_update_present.stat.exists
+
+{{%- endmacro -%}}
+
 
 {{#
 Macro for Ansible remediation for adding a kernel command line argument to the GRUB 2 bootloader.

shared/templates/accounts_password/ansible.template

@@ -29,6 +29,10 @@
 }}}
 {{% endif %}}
 
+{{% if "ubuntu" in product %}}
+{{{ ansible_pam_pwquality_enable('/usr/share/pam-configs/cac_pwquality') }}}
+{{% endif %}}
+
 - name: {{{ rule_title }}} - Ensure PAM variable {{{ VARIABLE }}} is set accordingly
   ansible.builtin.lineinfile:
     create: yes

shared/templates/accounts_password/bash.template

@@ -21,4 +21,8 @@ fi
 }}}
 {{% endif %}}
 
+{{% if product == "ubuntu2404" %}}
+{{{ bash_pam_pwquality_enable() }}}
+{{% endif %}}
+
 {{{ bash_replace_or_append('/etc/security/pwquality.conf', '^' ~ VARIABLE , '$var_password_pam_' ~ VARIABLE , '%s = %s') }}}

shared/templates/accounts_password/tests/correct_value.pass.sh

@@ -1,6 +1,10 @@
 #!/bin/bash
 # variables = var_password_pam_{{{ VARIABLE }}}={{{ TEST_VAR_VALUE }}}
 
+{{% if product == "ubuntu2404" %}}
+{{{ bash_pam_pwquality_enable() }}}
+{{% endif %}}
+
 truncate -s 0 /etc/security/pwquality.conf
 
 echo "{{{ VARIABLE }}} = {{{ TEST_CORRECT_VALUE }}}" >> /etc/security/pwquality.conf

shared/templates/accounts_password/tests/correct_value_directory.pass.sh

@@ -6,6 +6,10 @@
 # This test will ensure that OVAL also checks the configuration in 
 # /etc/security/pwquality.conf.d/*.conf files
 
+{{% if product == "ubuntu2404" %}}
+{{{ bash_pam_pwquality_enable() }}}
+{{% endif %}}
+
 truncate -s 0 /etc/security/pwquality.conf
 
 config_dir="/etc/security/pwquality.conf.d"

shared/templates/accounts_password/tests/duplicated_values.pass.sh

@@ -1,6 +1,10 @@
 #!/bin/bash
 # variables = var_password_pam_{{{ VARIABLE }}}={{{ TEST_VAR_VALUE }}}
 
+{{% if product == "ubuntu2404" %}}
+{{{ bash_pam_pwquality_enable() }}}
+{{% endif %}}
+
 truncate -s 0 /etc/security/pwquality.conf
 
 echo "{{{ VARIABLE }}} = {{{ TEST_CORRECT_VALUE }}}" >> /etc/security/pwquality.conf

shared/templates/accounts_password/tests/multiple_correct_value.pass.sh

@@ -3,6 +3,10 @@
 # platform = Oracle Linux 8
 # variables = var_password_pam_{{{ VARIABLE }}}={{{ TEST_VAR_VALUE }}}
 
+{{% if product == "ubuntu2404" %}}
+{{{ bash_pam_pwquality_enable() }}}
+{{% endif %}}
+
 truncate -s 0 /etc/security/pwquality.conf
 
 echo "{{{ VARIABLE }}} = {{{ TEST_CORRECT_VALUE }}}" >> /etc/security/pwquality.conf