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

6
require 'openssl'
7

8
class MetasploitModule < Msf::Auxiliary
9
  include Msf::Auxiliary::Report
10
  include Msf::Auxiliary::Scanner
11

12
  def initialize
13
    super(
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      'Name'        => 'UDP Service Prober',
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      'Description' => 'Detect common UDP services using sequential probes',
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      'Author'      => 'hdm',
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      'License'     => MSF_LICENSE
18
    )
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20
    register_options(
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      [
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        Opt::CHOST,
23
      ])
24

25
    register_advanced_options(
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      [
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        OptBool.new('RANDOMIZE_PORTS', [false, 'Randomize the order the ports are probed', true])
28
      ])
29

30
    # Initialize the probes array
31
    @probes = []
32

33
    # Add the UDP probe method names
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    @probes << 'probe_pkt_dns'
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    @probes << 'probe_pkt_netbios'
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    @probes << 'probe_pkt_portmap'
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    @probes << 'probe_pkt_mssql'
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    @probes << 'probe_pkt_ntp'
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    @probes << 'probe_pkt_snmp1'
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    @probes << 'probe_pkt_snmp2'
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    @probes << 'probe_pkt_sentinel'
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    @probes << 'probe_pkt_db2disco'
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    @probes << 'probe_pkt_citrix'
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    @probes << 'probe_pkt_pca_st'
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    @probes << 'probe_pkt_pca_nq'
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    @probes << 'probe_chargen'
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48
  end
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50
  def setup
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    super
52

53
    if datastore['RANDOMIZE_PORTS']
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      @probes = @probes.sort_by { rand }
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    end
56
  end
57

58
  # Fingerprint a single host
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  def run_host(ip)
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    @results = {}
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    @thost = ip
62

63
    begin
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      udp_sock = nil
65

66
      @probes.each do |probe|
67

68
      # Send each probe to each host
69

70
        begin
71
          data, port = self.send(probe, ip)
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          @tport = port
73

74
          # Create an unbound UDP socket if no CHOST is specified, otherwise
75
          # create a UDP socket bound to CHOST (in order to avail of pivoting)
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          udp_sock = Rex::Socket::Udp.create( {
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            'LocalHost' => datastore['CHOST'] || nil,
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            'PeerHost'  => ip, 'PeerPort' => port,
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            'Context' => {'Msf' => framework, 'MsfExploit' => self}
80
          })
81

82
          udp_sock.put(data)
83

84
          r = udp_sock.recvfrom(65535, 0.1) and r[1]
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          parse_reply(r) if r
86

87
        rescue ::Interrupt
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          raise $!
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        rescue ::Rex::HostUnreachable, ::Rex::ConnectionTimeout, ::Rex::ConnectionRefused, ::IOError
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          nil
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        ensure
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          udp_sock.close if udp_sock
93
        end
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95
      end
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    rescue ::Interrupt
97
      raise $!
98
    rescue ::Exception => e
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      print_error("Unknown error: #{@thost}:#{@tport} #{e.class} #{e} #{e.backtrace}")
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    end
101

102
    @results.each_key do |k|
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      next if not @results[k].respond_to?('keys')
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      data = @results[k]
105

106
      next unless inside_workspace_boundary?(data[:host])
107

108
      conf = {
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        :host  => data[:host],
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        :port  => data[:port],
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        :proto => 'udp',
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        :name  => data[:app],
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        :info  => data[:info]
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      }
115

116
      if data[:hname]
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        conf[:host_name] = data[:hname].downcase
118
      end
119

120
      if data[:mac]
121
        conf[:mac] = data[:mac].downcase
122
      end
123

124
      report_service(conf)
125
      print_good("Discovered #{data[:app]} on #{k} (#{data[:info]})")
126
    end
127
  end
128

129

130
  #
131
  # The response parsers
132
  #
133
  def parse_reply(pkt)
134

135
    # Ignore "empty" packets
136
    return if not pkt[1]
137

138
    if(pkt[1] =~ /^::ffff:/)
139
      pkt[1] = pkt[1].sub(/^::ffff:/, '')
140
    end
141

142
    app = 'unknown'
143
    inf = ''
144
    maddr = nil
145
    hname = nil
146

147
    hkey = "#{pkt[1]}:#{pkt[2]}"
148

149
    # Work with protocols that return different data in different packets
150
    # These are reported at the end of the scanning loop to build state
151
    case pkt[2]
152
      when 5632
153

154
        @results[hkey] ||= {}
155
        data = @results[hkey]
156
        data[:app]  = "pcAnywhere_stat"
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        data[:port] = pkt[2]
158
        data[:host] = pkt[1]
159

160
        case pkt[0]
161

162
        when /^NR(........................)(........)/
163
          name = $1.dup
164
          caps = $2.dup
165
          name = name.gsub(/_+$/, '').gsub("\x00", '').strip
166
          caps = caps.gsub(/_+$/, '').gsub("\x00", '').strip
167
          data[:name] = name
168
          data[:caps] = caps
169

170
        when /^ST(.+)/
171
          buff = $1.dup
172
          stat = 'Unknown'
173

174
          if buff[2,1].unpack("C")[0] == 67
175
            stat = "Available"
176
          end
177

178
          if buff[2,1].unpack("C")[0] == 11
179
            stat = "Busy"
180
          end
181

182
          data[:stat] = stat
183
        end
184

185
        if data[:name]
186
          inf << "Name: #{data[:name]} "
187
        end
188

189
        if data[:stat]
190
          inf << "- #{data[:stat]} "
191
        end
192

193
        if data[:caps]
194
          inf << "( #{data[:caps]} ) "
195
        end
196
        data[:info] = inf
197
    end
198

199

200
    # Ignore duplicates for the protocols below
201
    return if @results[hkey]
202

203
    case pkt[2]
204

205
      when 19
206
        app = 'chargen'
207
        return unless chargen_parse(pkt[0])
208
        @results[hkey] = true
209

210
      when 53
211
        app = 'DNS'
212
        ver = nil
213

214
        if (not ver and pkt[0] =~ /([6789]\.[\w\.\-_\:\(\)\[\]\/\=\+\|\{\}]+)/i)
215
          ver = 'BIND ' + $1
216
        end
217

218
        ver = 'Microsoft DNS' if (not ver and pkt[0][2,4] == "\x81\x04\x00\x01")
219
        ver = 'TinyDNS'       if (not ver and pkt[0][2,4] == "\x81\x81\x00\x01")
220

221
        ver = pkt[0].unpack('H*')[0] if not ver
222
        inf = ver if ver
223
        @results[hkey] = true
224

225
      when 137
226
        app = 'NetBIOS'
227

228
        data = pkt[0]
229

230
        head = data.slice!(0,12)
231

232
        xid, flags, quests, answers, auths, adds = head.unpack('n6')
233
        return if quests != 0
234
        return if answers == 0
235

236
        qname = data.slice!(0,34)
237
        rtype,rclass,rttl,rlen = data.slice!(0,10).unpack('nnNn')
238
        buff = data.slice!(0,rlen)
239

240
        names = []
241

242
        case rtype
243
        when 0x21
244
          rcnt = buff.slice!(0,1).unpack("C")[0]
245
          1.upto(rcnt) do
246
            tname = buff.slice!(0,15).gsub(/\x00.*/, '').strip
247
            ttype = buff.slice!(0,1).unpack("C")[0]
248
            tflag = buff.slice!(0,2).unpack('n')[0]
249
            names << [ tname, ttype, tflag ]
250
          end
251
          maddr = buff.slice!(0,6).unpack("C*").map{|c| "%.2x" % c }.join(":")
252

253
          names.each do |name|
254
            inf << name[0]
255
            inf << ":<%.2x>" % name[1]
256
            if (name[2] & 0x8000 == 0)
257
              inf << ":U :"
258
            else
259
              inf << ":G :"
260
            end
261
          end
262
          inf << maddr
263

264
          if(names.length > 0)
265
            hname = names[0][0]
266
          end
267
        end
268

269
        @results[hkey] = true
270

271
      when 111
272
        app = 'Portmap'
273
        buf = pkt[0]
274
        inf = ""
275
        hed = buf.slice!(0,24)
276
        svc = []
277
        while(buf.length >= 20)
278
          rec = buf.slice!(0,20).unpack("N5")
279
          svc << "#{rec[1]} v#{rec[2]} #{rec[3] == 0x06 ? "TCP" : "UDP"}(#{rec[4]})"
280
          report_service(
281
            :host => pkt[1],
282
            :port => rec[4],
283
            :proto => (rec[3] == 0x06 ? "tcp" : "udp"),
284
            :name => "sunrpc",
285
            :info => "#{rec[1]} v#{rec[2]}"
286
          )
287
        end
288
        inf = svc.join(", ")
289
        @results[hkey] = true
290

291
      when 123
292
        app = 'NTP'
293
        ver = nil
294
        ver = pkt[0].unpack('H*')[0]
295
        ver = 'NTP v3'                  if (ver =~ /^1c06|^1c05/)
296
        ver = 'NTP v4'                  if (ver =~ /^240304/)
297
        ver = 'NTP v4 (unsynchronized)' if (ver =~ /^e40/)
298
        ver = 'Microsoft NTP'           if (ver =~ /^dc00|^dc0f/)
299
        inf = ver if ver
300
        @results[hkey] = true
301

302
      when 1434
303
        app = 'MSSQL'
304
        mssql_ping_parse(pkt[0]).each_pair { |k,v|
305
          inf += k+'='+v+' '
306
        }
307
        @results[hkey] = true
308

309
      when 161
310
        app = 'SNMP'
311

312
        asn = OpenSSL::ASN1.decode(pkt[0]) rescue nil
313
        return if not asn
314

315
        snmp_error = asn.value[0].value rescue nil
316
        snmp_comm  = asn.value[1].value rescue nil
317
        snmp_data  = asn.value[2].value[3].value[0] rescue nil
318
        snmp_oid   = snmp_data.value[0].value rescue nil
319
        snmp_info  = snmp_data.value[1].value rescue nil
320

321
        return if not (snmp_error and snmp_comm and snmp_data and snmp_oid and snmp_info)
322
        snmp_info = snmp_info.to_s.gsub(/\s+/, ' ')
323

324
        inf = snmp_info
325
        com = snmp_comm
326
        @results[hkey] = true
327

328
      when 5093
329
        app = 'Sentinel'
330
        @results[hkey] = true
331

332
      when 523
333
        app = 'ibm-db2'
334
        inf = db2disco_parse(pkt[0])
335
        @results[hkey] = true
336

337
      when 1604
338
        app = 'citrix-ica'
339
        return unless citrix_parse(pkt[0])
340
        @results[hkey] = true
341

342
    end
343

344
    return unless inside_workspace_boundary?(pkt[1])
345
    report_service(
346
      :host  => pkt[1],
347
      :mac   => (maddr and maddr != '00:00:00:00:00:00') ? maddr : nil,
348
      :host_name => (hname) ? hname.downcase : nil,
349
      :port  => pkt[2],
350
      :proto => 'udp',
351
      :name  => app,
352
      :info  => inf
353
    )
354

355
    print_good("Discovered #{app} on #{pkt[1]}:#{pkt[2]} (#{inf})")
356

357
  end
358

359

360
  #
361
  # Parse a db2disco packet.
362
  #
363
  def db2disco_parse(data)
364
    res = data.split("\x00")
365
    "#{res[2]}_#{res[1]}"
366
  end
367

368
  #
369
  # Validate a chargen packet.
370
  #
371
  def chargen_parse(data)
372
    data =~ /ABCDEFGHIJKLMNOPQRSTUVWXYZ|0123456789/i
373
  end
374

375
  #
376
  # Validate this is truly Citrix ICA; returns true or false.
377
  #
378
  def citrix_parse(data)
379
    server_response = "\x30\x00\x02\x31\x02\xfd\xa8\xe3\x02\x00\x06\x44" # Server hello response
380
    data =~ /^#{server_response}/
381
  end
382

383
  #
384
  # Parse a 'ping' response and format as a hash
385
  #
386
  def mssql_ping_parse(data)
387
    res = {}
388
    var = nil
389
    idx = data.index('ServerName')
390
    return res if not idx
391

392
    data[idx, data.length-idx].split(';').each do |d|
393
      if (not var)
394
        var = d
395
      else
396
        if (var.length > 0)
397
          res[var] = d
398
          var = nil
399
        end
400
      end
401
    end
402

403
    return res
404
  end
405

406
  #
407
  # The probe definitions
408
  #
409

410
  def probe_chargen(ip)
411
    pkt = Rex::Text.rand_text_alpha_lower(1)
412
    return [pkt, 19]
413
  end
414

415
  def probe_pkt_dns(ip)
416
    data = [rand(0xffff)].pack('n') +
417
    "\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00"+
418
    "\x07"+ "VERSION"+
419
    "\x04"+ "BIND"+
420
    "\x00\x00\x10\x00\x03"
421

422
    return [data, 53]
423
  end
424

425
  def probe_pkt_netbios(ip)
426
    data =
427
    [rand(0xffff)].pack('n')+
428
    "\x00\x00\x00\x01\x00\x00\x00\x00"+
429
    "\x00\x00\x20\x43\x4b\x41\x41\x41"+
430
    "\x41\x41\x41\x41\x41\x41\x41\x41"+
431
    "\x41\x41\x41\x41\x41\x41\x41\x41"+
432
    "\x41\x41\x41\x41\x41\x41\x41\x41"+
433
    "\x41\x41\x41\x00\x00\x21\x00\x01"
434

435
    return [data, 137]
436
  end
437

438
  def probe_pkt_portmap(ip)
439
    data =
440
    [
441
      rand(0xffffffff), # XID
442
      0,              # Type
443
      2,              # RPC Version
444
      100000,         # Program ID
445
      2,              # Program Version
446
      4,              # Procedure
447
      0, 0,   # Credentials
448
      0, 0,   # Verifier
449
    ].pack('N*')
450

451
    return [data, 111]
452
  end
453

454
  def probe_pkt_mssql(ip)
455
    return ["\x02", 1434]
456
  end
457

458
  def probe_pkt_ntp(ip)
459
    data =
460
      "\xe3\x00\x04\xfa\x00\x01\x00\x00\x00\x01\x00\x00\x00" +
461
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
462
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
463
      "\x00\xc5\x4f\x23\x4b\x71\xb1\x52\xf3"
464
    return [data, 123]
465
  end
466

467

468
  def probe_pkt_sentinel(ip)
469
    return ["\x7a\x00\x00\x00\x00\x00", 5093]
470
  end
471

472
  def probe_pkt_snmp1(ip)
473
    version = 1
474
    data = OpenSSL::ASN1::Sequence([
475
      OpenSSL::ASN1::Integer(version - 1),
476
      OpenSSL::ASN1::OctetString("public"),
477
      OpenSSL::ASN1::Set.new([
478
        OpenSSL::ASN1::Integer(rand(0x80000000)),
479
        OpenSSL::ASN1::Integer(0),
480
        OpenSSL::ASN1::Integer(0),
481
        OpenSSL::ASN1::Sequence([
482
          OpenSSL::ASN1::Sequence([
483
            OpenSSL::ASN1.ObjectId("1.3.6.1.2.1.1.1.0"),
484
            OpenSSL::ASN1.Null(nil)
485
          ])
486
        ]),
487
      ], 0, :IMPLICIT)
488
    ]).to_der
489
    [data, 161]
490
  end
491

492
  def probe_pkt_snmp2(ip)
493
    version = 2
494
    data = OpenSSL::ASN1::Sequence([
495
      OpenSSL::ASN1::Integer(version - 1),
496
      OpenSSL::ASN1::OctetString("public"),
497
      OpenSSL::ASN1::Set.new([
498
        OpenSSL::ASN1::Integer(rand(0x80000000)),
499
        OpenSSL::ASN1::Integer(0),
500
        OpenSSL::ASN1::Integer(0),
501
        OpenSSL::ASN1::Sequence([
502
          OpenSSL::ASN1::Sequence([
503
            OpenSSL::ASN1.ObjectId("1.3.6.1.2.1.1.1.0"),
504
            OpenSSL::ASN1.Null(nil)
505
          ])
506
        ]),
507
      ], 0, :IMPLICIT)
508
    ]).to_der
509
    [data, 161]
510
  end
511

512
  def probe_pkt_db2disco(ip)
513
    data = "DB2GETADDR\x00SQL05000\x00"
514
    [data, 523]
515
  end
516

517
  def probe_pkt_citrix(ip) # Server hello packet from citrix_published_bruteforce
518
    data =
519
      "\x1e\x00\x01\x30\x02\xfd\xa8\xe3\x00\x00\x00\x00\x00" +
520
      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
521
      "\x00\x00\x00\x00"
522
    return [data, 1604]
523
  end
524

525
  def probe_pkt_pca_st(ip)
526
    return ["ST", 5632]
527
  end
528

529
  def probe_pkt_pca_nq(ip)
530
    return ["NQ", 5632]
531
  end
532
end
533

534