Set Deny For Failed Password Attempts

An XCCDF Rule

Description

The SUSE Linux Enterprise 12 operating system must lock an account after - at most - consecutive invalid access attempts.

Rationale

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. To configure the operating system to lock an account after three unsuccessful consecutive access attempts using pam_tally2.so, modify the content of both /etc/pam.d/login and /etc/pam.d/common-account as follows:

add or modify the pam_tally2.so module line in /etc/pam.d/login to ensure both onerr=fail and deny= are present. For example:
```
auth required pam_tally2.so onerr=fail silent audit deny=
```
add or modify the following line in /etc/pam.d/common-account:
```
account required pam_tally2.so
```

ID: xccdf_org.ssgproject.content_rule_accounts_passwords_pam_tally2
Severity: Medium
References: CCI-000044

AC-7(a)

Req-8.1.6

8.3.4

SRG-OS-000021-GPOS-00005

SLES-12-010130

5.3.2

SV-217114r603262_rule

CCE-83055-4

BP28(R18)
Updated: about 1 year ago

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_tally2='<xccdf-1.2:sub xmlns:xccdf-1.2="http://checklists.nist.gov/xccdf/1.2" idref="xccdf_org.ssgproject.content_value_var_password_pam_tally2" use="legacy"/>'

# Use a non-number regexp to force update of the value of the deny option



if ! grep -qP '^\s*auth\s+'"required"'\s+pam_tally2.so\s*.*' "/etc/pam.d/login"; then
    # Line matching group + control + module was not found. Check group + module.
    if [ "$(grep -cP '^\s*auth\s+.*\s+pam_tally2.so\s*' "/etc/pam.d/login")" -eq 1 ]; then
        # The control is updated only if one single line matches.
        sed -i -E --follow-symlinks 's/^(\s*auth\s+).*(\bpam_tally2.so.*)/\1'"required"' \2/' "/etc/pam.d/login"
    else
        echo 'auth    '"required"'    pam_tally2.so' >> "/etc/pam.d/login"
    fi
fi
# Check the option
if ! grep -qP '^\s*auth\s+'"required"'\s+pam_tally2.so\s*.*\sdeny\b' "/etc/pam.d/login"; then
    sed -i -E --follow-symlinks '/\s*auth\s+'"required"'\s+pam_tally2.so.*/ s/$/ deny='"${var_password_pam_tally2}"'/' "/etc/pam.d/login"
else
    sed -i -E --follow-symlinks 's/(\s*auth\s+'"required"'\s+pam_tally2.so\s+.*)('"deny"'=)[[:alnum:]]+\s*(.*)/\1\2'"${var_password_pam_tally2}"' \3/' "/etc/pam.d/login"
fi
if ! grep -qP '^\s*auth\s+'"required"'\s+pam_tally2.so\s*.*' "/etc/pam.d/login"; then
    # Line matching group + control + module was not found. Check group + module.
    if [ "$(grep -cP '^\s*auth\s+.*\s+pam_tally2.so\s*' "/etc/pam.d/login")" -eq 1 ]; then
        # The control is updated only if one single line matches.
        sed -i -E --follow-symlinks 's/^(\s*auth\s+).*(\bpam_tally2.so.*)/\1'"required"' \2/' "/etc/pam.d/login"
    else
        LAST_MATCH_LINE=$(grep -nP "(fail)" "/etc/pam.d/login" | tail -n 1 | cut -d: -f 1)
        if [ ! -z $LAST_MATCH_LINE ]; then
            sed -i --follow-symlinks $LAST_MATCH_LINE' a auth     '"required"'    pam_tally2.so' "/etc/pam.d/login"
        else
            echo 'auth    '"required"'    pam_tally2.so' >> "/etc/pam.d/login"
        fi
    fi
fi
# Check the option
if ! grep -qP '^\s*auth\s+'"required"'\s+pam_tally2.so\s*.*\sonerr\b' "/etc/pam.d/login"; then
    sed -i -E --follow-symlinks '/\s*auth\s+'"required"'\s+pam_tally2.so.*/ s/$/ onerr='"fail"'/' "/etc/pam.d/login"
else
    sed -i -E --follow-symlinks 's/(\s*auth\s+'"required"'\s+pam_tally2.so\s+.*)('"onerr"'=)[[:alnum:]]+\s*(.*)/\1\2'"fail"' \3/' "/etc/pam.d/login"
fi
if ! grep -qP '^\s*account\s+'"required"'\s+pam_tally2.so\s*.*' "/etc/pam.d/common-account"; then
    # Line matching group + control + module was not found. Check group + module.
    if [ "$(grep -cP '^\s*account\s+.*\s+pam_tally2.so\s*' "/etc/pam.d/common-account")" -eq 1 ]; then
        # The control is updated only if one single line matches.
        sed -i -E --follow-symlinks 's/^(\s*account\s+).*(\bpam_tally2.so.*)/\1'"required"' \2/' "/etc/pam.d/common-account"
    else
        echo 'account    '"required"'    pam_tally2.so' >> "/etc/pam.d/common-account"
    fi
fi
# Check the option
if ! grep -qP '^\s*account\s+'"required"'\s+pam_tally2.so\s*.*\s\b' "/etc/pam.d/common-account"; then
    sed -i -E --follow-symlinks '/\s*account\s+'"required"'\s+pam_tally2.so.*/ s/$/ /' "/etc/pam.d/common-account"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
- name: XCCDF Value var_password_pam_tally2 # promote to variable
  set_fact:
    var_password_pam_tally2: !!str <xccdf-1.2:sub xmlns:xccdf-1.2="http://checklists.nist.gov/xccdf/1.2" idref="xccdf_org.ssgproject.content_value_var_password_pam_tally2" use="legacy"/>
  tags:
    - always

- name: Set Deny For Failed Password Attempts - Check if expected PAM module line
    is present in /etc/pam.d/login
  ansible.builtin.lineinfile:
    path: /etc/pam.d/login
    regexp: ^\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*
    state: absent
  check_mode: true
  changed_when: false
  register: result_pam_line_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Include or update the PAM module line
    in /etc/pam.d/login
  block:

  - name: Set Deny For Failed Password Attempts - Check if required PAM module line
      is present in /etc/pam.d/login with different control
    ansible.builtin.lineinfile:
      path: /etc/pam.d/login
      regexp: ^\s*auth\s+.*\s+pam_tally2.so\s*
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_line_other_control_present

  - name: Set Deny For Failed Password Attempts - Ensure the correct control for the
      required PAM module line in /etc/pam.d/login
    ansible.builtin.replace:
      dest: /etc/pam.d/login
      regexp: ^(\s*auth\s+).*(\bpam_tally2.so.*)
      replace: \1required \2
    register: result_pam_module_edit
    when:
    - result_pam_line_other_control_present.found == 1

  - name: Set Deny For Failed Password Attempts - Ensure the required PAM module line
      is included in /etc/pam.d/login
    ansible.builtin.lineinfile:
      dest: /etc/pam.d/login
      line: auth    required    pam_tally2.so
    register: result_pam_module_add
    when:
    - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
      > 1

  - name: Set Deny For Failed Password Attempts - Ensure authselect changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_present is defined
    - result_authselect_present.stat.exists
    - |-
      (result_pam_module_add is defined and result_pam_module_add.changed)
       or (result_pam_module_edit is defined and result_pam_module_edit.changed)
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_line_present.found is defined
  - result_pam_line_present.found == 0
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Check if the required PAM module option
    is present in /etc/pam.d/login
  ansible.builtin.lineinfile:
    path: /etc/pam.d/login
    regexp: ^\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*\sdeny\b
    state: absent
  check_mode: true
  changed_when: false
  register: result_pam_module_deny_option_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Ensure the "deny" PAM option for "pam_tally2.so"
    is included in /etc/pam.d/login
  ansible.builtin.lineinfile:
    path: /etc/pam.d/login
    backrefs: true
    regexp: ^(\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so.*)
    line: \1 deny={{ var_password_pam_tally2 }}
    state: present
  register: result_pam_deny_add
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_module_deny_option_present.found == 0
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Ensure the required value for "deny"
    PAM option from "pam_tally2.so" in /etc/pam.d/login
  ansible.builtin.lineinfile:
    path: /etc/pam.d/login
    backrefs: true
    regexp: ^(\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s+.*)(deny)=[0-9a-zA-Z]+\s*(.*)
    line: \1\2={{ var_password_pam_tally2 }} \3
  register: result_pam_deny_edit
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_module_deny_option_present.found > 0
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Check if expected PAM module line
    is present in /etc/pam.d/login
  ansible.builtin.lineinfile:
    path: /etc/pam.d/login
    regexp: ^\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*
    state: absent
  check_mode: true
  changed_when: false
  register: result_pam_line_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Include or update the PAM module line
    in /etc/pam.d/login
  block:

  - name: Set Deny For Failed Password Attempts - Check if required PAM module line
      is present in /etc/pam.d/login with different control
    ansible.builtin.lineinfile:
      path: /etc/pam.d/login
      regexp: ^\s*auth\s+.*\s+pam_tally2.so\s*
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_line_other_control_present

  - name: Set Deny For Failed Password Attempts - Ensure the correct control for the
      required PAM module line in /etc/pam.d/login
    ansible.builtin.replace:
      dest: /etc/pam.d/login
      regexp: ^(\s*auth\s+).*(\bpam_tally2.so.*)
      replace: \1required \2
    register: result_pam_module_edit
    when:
    - result_pam_line_other_control_present.found == 1

  - name: Set Deny For Failed Password Attempts - Ensure the required PAM module line
      is included in /etc/pam.d/login
    ansible.builtin.lineinfile:
      dest: /etc/pam.d/login
      insertafter: (fail)
      line: auth    required    pam_tally2.so
    register: result_pam_module_add
    when:
    - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
      > 1

  - name: Set Deny For Failed Password Attempts - Ensure authselect changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_present is defined
    - result_authselect_present.stat.exists
    - |-
      (result_pam_module_add is defined and result_pam_module_add.changed)
       or (result_pam_module_edit is defined and result_pam_module_edit.changed)
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_line_present.found is defined
  - result_pam_line_present.found == 0
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Check if the required PAM module option
    is present in /etc/pam.d/login
  ansible.builtin.lineinfile:
    path: /etc/pam.d/login
    regexp: ^\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*\sonerr\b
    state: absent
  check_mode: true
  changed_when: false
  register: result_pam_module_onerr_option_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Ensure the "onerr" PAM option for
    "pam_tally2.so" is included in /etc/pam.d/login
  ansible.builtin.lineinfile:
    path: /etc/pam.d/login
    backrefs: true
    regexp: ^(\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so.*)
    line: \1 onerr=fail
    state: present
  register: result_pam_onerr_add
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_module_onerr_option_present.found == 0
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Ensure the required value for "onerr"
    PAM option from "pam_tally2.so" in /etc/pam.d/login
  ansible.builtin.lineinfile:
    path: /etc/pam.d/login
    backrefs: true
    regexp: ^(\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s+.*)(onerr)=[0-9a-zA-Z]+\s*(.*)
    line: \1\2=fail \3
  register: result_pam_onerr_edit
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_module_onerr_option_present.found > 0
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Check if expected PAM module line
    is present in /etc/pam.d/common-account
  ansible.builtin.lineinfile:
    path: /etc/pam.d/common-account
    regexp: ^\s*account\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*
    state: absent
  check_mode: true
  changed_when: false
  register: result_pam_line_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Include or update the PAM module line
    in /etc/pam.d/common-account
  block:

  - name: Set Deny For Failed Password Attempts - Check if required PAM module line
      is present in /etc/pam.d/common-account with different control
    ansible.builtin.lineinfile:
      path: /etc/pam.d/common-account
      regexp: ^\s*account\s+.*\s+pam_tally2.so\s*
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_line_other_control_present

  - name: Set Deny For Failed Password Attempts - Ensure the correct control for the
      required PAM module line in /etc/pam.d/common-account
    ansible.builtin.replace:
      dest: /etc/pam.d/common-account
      regexp: ^(\s*account\s+).*(\bpam_tally2.so.*)
      replace: \1required \2
    register: result_pam_module_edit
    when:
    - result_pam_line_other_control_present.found == 1

  - name: Set Deny For Failed Password Attempts - Ensure the required PAM module line
      is included in /etc/pam.d/common-account
    ansible.builtin.lineinfile:
      dest: /etc/pam.d/common-account
      line: account    required    pam_tally2.so
    register: result_pam_module_add
    when:
    - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
      > 1

  - name: Set Deny For Failed Password Attempts - Ensure authselect changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_present is defined
    - result_authselect_present.stat.exists
    - |-
      (result_pam_module_add is defined and result_pam_module_add.changed)
       or (result_pam_module_edit is defined and result_pam_module_edit.changed)
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_line_present.found is defined
  - result_pam_line_present.found == 0
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Check if the required PAM module option
    is present in /etc/pam.d/common-account
  ansible.builtin.lineinfile:
    path: /etc/pam.d/common-account
    regexp: ^\s*account\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*\s\b
    state: absent
  check_mode: true
  changed_when: false
  register: result_pam_module__option_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set Deny For Failed Password Attempts - Ensure the "" PAM option for "pam_tally2.so"
    is included in /etc/pam.d/common-account
  ansible.builtin.lineinfile:
    path: /etc/pam.d/common-account
    backrefs: true
    regexp: ^(\s*account\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so.*)
    line: \1
    state: present
  register: result_pam__add
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_module__option_present.found == 0
  tags:
  - CCE-83055-4
  - DISA-STIG-SLES-12-010130
  - NIST-800-53-AC-7(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_tally2
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Set Deny For Failed Password Attempts

Description

Rationale

Remediation - Shell Script

Remediation - Ansible