Puppet Class: cis_security_hardening::rules::nftables_loopback

Defined in:
manifests/rules/nftables_loopback.pp

Summary

Ensure loopback traffic is configured

Overview

Configure the loopback interface to accept traffic. Configure all other interfaces to deny traffic to the loopback network.

Rationale: Loopback traffic is generated between processes on machine and is typically critical to operation of the system. The loopback interface is the only place that loopback network traffic should be seen, all other interfaces should ignore traffic on this network as an anti- spoofing measure.

Examples:

class { 'cis_security_hardening::rules::nftables_loopback':
    enforce => true,
    table => 'default',
}

Parameters:

  • enforce (Boolean) (defaults to: false) —

    Enforce the rule

  • table (String) (defaults to: 'default') —

    nftable table to add rules



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# File 'manifests/rules/nftables_loopback.pp', line 25

class cis_security_hardening::rules::nftables_loopback (
  Boolean $enforce = false,
  String $table    = 'default',
) {
  if $enforce {
    exec { 'nftables add local interface':
      command => "nft add rule ${table} filter input iif lo accept", #lint:ignore:security_class_or_define_parameter_in_exec
      path    => ['/bin', '/usr/bin', '/sbin', '/usr/sbin'],
      onlyif  => "test -z \"$(nft list ruleset ${table} | grep 'iif \"lo\" accept')\"",
      notify  => Exec['dump nftables ruleset'],
      require => Package['nftables'],
    }

    exec { 'nftables add local network':
      command => "nft add rule ${table} filter input ip saddr 127.0.0.0/8 counter drop", #lint:ignore:security_class_or_define_parameter_in_exec lint:ignore:140chars
      path    => ['/bin', '/usr/bin', '/sbin', '/usr/sbin'],
      onlyif  => "test -z \"$(nft list ruleset ${table} | grep -E 'ip\\s*saddr\\s*127.0.0.0/8\\s*counter\\s*packets.*drop')\"",
      notify  => Exec['dump nftables ruleset'],
      require => Package['nftables'],
    }

    exec { 'nftables ip6 traffic':
      command => "nft add rule ${table} filter input ip6 saddr ::1 counter drop", #lint:ignore:security_class_or_define_parameter_in_exec lint:ignore:140chars
      path    => ['/bin', '/usr/bin', '/sbin', '/usr/sbin'],
      onlyif  => "test -z \"$(nft list ruleset ${table} | grep 'ip6 saddr ::1 counter packets')\"",
      notify  => Exec['dump nftables ruleset'],
      require => Package['nftables'],
    }
  }
}