Puppet Class: os_hardening::suid_sgid

Defined in:
manifests/suid_sgid.pp

Overview

Class: os_hardening::suid_sgid

Minimize SUID and SGID bits.

Parameters:

  • whitelist (Array) (defaults to: [])
  • blacklist (Array) (defaults to: [])
  • remove_from_unknown (Boolean) (defaults to: false)
  • dry_run_on_unknown (Boolean) (defaults to: false) 


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# File 'manifests/suid_sgid.pp', line 20

class os_hardening::suid_sgid (
  Array   $whitelist           = [],
  Array   $blacklist           = [],
  Boolean $remove_from_unknown = false,
  Boolean $dry_run_on_unknown  = false,
) {
  # suid and sgid blacklists and whitelists
  # ---------------------------------------
  # don't change values in the system_blacklist/whitelist
  # adjust values for blacklist/whitelist instead,
  # they can override system_blacklist/whitelist

  # list of suid/sgid entries that must be removed
  $system_blacklist = [
    # blacklist as provided by NSA
    '/usr/bin/rcp', '/usr/bin/rlogin', '/usr/bin/rsh',
    # sshd must not use host-based authentication (see ssh cookbook)
    '/usr/libexec/openssh/ssh-keysign',
    '/usr/lib/openssh/ssh-keysign',
    # misc others
    # not normally required for user
    '/sbin/netreport',
    # modify interfaces via functional accounts
    '/usr/sbin/usernetctl',
    # connecting to ...
    # no isdn...
    '/usr/sbin/userisdnctl',
    # no ppp / dsl ...
    '/usr/sbin/pppd',
    # lockfile
    '/usr/bin/lockfile',
    '/usr/bin/mail-lock',
    '/usr/bin/mail-unlock',
    '/usr/bin/mail-touchlock',
    '/usr/bin/dotlockfile',
    # need more investigation, blacklist for now
    '/usr/bin/arping',
    '/usr/sbin/uuidd',
    # investigate current state...
    '/usr/bin/mtr',
    # investigate current state...
    '/usr/lib/evolution/camel-lock-helper-1.2',
    # pseudo-tty, needed?
    '/usr/lib/pt_chown',
    '/usr/lib/eject/dmcrypt-get-device',
    # midnight commander screensaver
    '/usr/lib/mc/cons.saver',
  ]

  # list of suid/sgid entries that can remain untouched
  $system_whitelist = [
    # whitelist as provided by NSA
    '/bin/mount', '/bin/ping', '/bin/su', '/bin/umount',
    '/sbin/pam_timestamp_check','/sbin/unix_chkpwd', '/usr/bin/at',
    '/usr/bin/gpasswd', '/usr/bin/locate', '/usr/bin/newgrp',
    '/usr/bin/passwd', '/usr/bin/ssh-agent', '/usr/libexec/utempter/utempter',
    '/usr/sbin/lockdev', '/usr/sbin/sendmail.sendmail', '/usr/bin/expiry',
    # whitelist ipv6
    '/bin/ping6','/usr/bin/traceroute6.iputils',
    # whitelist nfs
    '/sbin/mount.nfs', '/sbin/umount.nfs',
    # whitelist nfs4
    '/sbin/mount.nfs4', '/sbin/umount.nfs4',
    # whitelist cron
    '/usr/bin/crontab',
    # whitelist consolemssaging
    '/usr/bin/wall', '/usr/bin/write',
    # whitelist: only SGID with utmp group for multi-session access
    #            impact is limited; installation/usage has some remaining risk
    '/usr/bin/screen',
    # whitelist locate
    '/usr/bin/mlocate',
    # whitelist usermanagement
    '/usr/bin/chage', '/usr/bin/chfn', '/usr/bin/chsh',
    # whitelist fuse
    '/bin/fusermount',
    # whitelist pkexec
    '/usr/bin/pkexec',
    # whitelist sudo
    '/usr/bin/sudo','/usr/bin/sudoedit',
    # whitelist postfix
    '/usr/sbin/postdrop','/usr/sbin/postqueue',
    # whitelist apache
    '/usr/sbin/suexec',
    # whitelist squid
    '/usr/lib/squid/ncsa_auth', '/usr/lib/squid/pam_auth',
    # whitelist kerberos
    '/usr/kerberos/bin/ksu',
    # whitelist pam_caching
    '/usr/sbin/ccreds_validate',
    # whitelist Xorg
    '/usr/bin/Xorg',
    '/usr/bin/X',
    # freedesktop ipc
    '/usr/lib/dbus-1.0/dbus-daemon-launch-helper',
    # gnome
    '/usr/lib/vte/gnome-pty-helper',
    '/usr/lib/libvte9/gnome-pty-helper',
    '/usr/lib/libvte-2.90-9/gnome-pty-helper',
  ]

  $final_blacklist = combine_sugid_lists($system_blacklist, $whitelist, $blacklist)
  $final_whitelist = combine_sugid_lists($system_whitelist, $blacklist, $whitelist)

  os_hardening::blacklist_files { $final_blacklist: }

  if $remove_from_unknown {
    # create a helper script
    # TODO: do without
    file { '/usr/local/sbin/remove_suids':
      ensure  => file,
      owner   => 'root',
      group   => 'root',
      mode    => '0500',
      content => template('os_hardening/remove_sugid_bits.erb'),
    }
    #remove all bits
    exec { 'remove SUID/SGID bits from unknown':
      command => '/usr/local/sbin/remove_suids',
    }
    File['/usr/local/sbin/remove_suids'] -> Exec['remove SUID/SGID bits from unknown']
  }
}