msfvenom

#!/usr/bin/env ruby
#
# $Id$
# $Revision$
#
msfbase = __FILE__
while File.symlink?(msfbase)
	msfbase = File.expand_path(File.readlink(msfbase), File.dirname(msfbase))
end

$:.unshift(File.join(File.dirname(msfbase), 'lib'))
$:.unshift(ENV['MSF_LOCAL_LIB']) if ENV['MSF_LOCAL_LIB']

Status = "[*] "
Error = "[-] "

require 'rex'
require 'msf/ui'
require 'msf/base'
require 'optparse'

def parse_args
	opts = {}
	datastore = {}
	opt = OptionParser.new
	opt.banner = "Usage: #{$0} [options] <var=val>"
	opt.separator('')
	opt.separator('Options:')

	opt.on('-p', '--payload    [payload]', String, 'Payload to use. Specify a \'-\' or stdin to use custom payloads') do |p|
		if p == '-'
			opts[:payload] = 'stdin'
		else
			opts[:payload] = p
		end
	end

	opt.on('-l', '--list       [module_type]', Array, 'List a module type example: payloads, encoders, nops, all') do |l|
		if l.nil? or l.empty?
			l = ["all"]
		end
		opts[:list] = l
	end

	opt.on('-n', '--nopsled    [length]', Integer, 'Prepend a nopsled of [length] size on to the payload') do |n|
		opts[:nopsled] = n.to_i
	end

	formats = Msf::Simple::Buffer.transform_formats + Msf::Util::EXE.to_executable_fmt_formats
	opt.on('-f', '--format     [format]', String, "Format to output results in: #{formats.join(', ')}") do |f|
		opts[:format] = f
	end

	opt.on('-e', '--encoder    [encoder]', String, 'The encoder to use') do |e|
		opts[:encode] = true
		opts[:encoder] = e
	end

	opt.on('-a', '--arch       [architecture]', String, 'The architecture to use') do |a|
		opts[:arch] = a
	end

	opt.on('', '--platform   [platform]', String, 'The platform of the payload') do |l|
		opts[:platform] = Msf::Module::PlatformList.transform(l)
	end

	opt.on('-s', '--space      [length]', Integer, 'The maximum size of the resulting payload') do |s|
		opts[:space] = s
	end

	opt.on('-b', '--bad-chars  [list] ', String, 'The list of characters to avoid example: \'\x00\xff\'') do |b|
		opts[:badchars] = Rex::Text.hex_to_raw(b)
	end

	opt.on('-i', '--iterations [count] ', Integer, 'The number of times to encode the payload') do |i|
		opts[:iterations] = i
	end

	opt.on('-c', '--add-code   [path] ', String, 'Specify an additional win32 shellcode file to include') do |x|
		opts[:addshellcode] = x
	end

	opt.on('-x', '--template   [path] ', String, 'Specify a custom executable file to use as a template') do |x|
		opts[:template] = x
		unless File.exist?(x)
			$stderr.puts "Template file (#{x}) does not exist"
			exit 1
		end
	end

	opt.on('-k', '--keep', 'Preserve the template behavior and inject the payload as a new thread') do
		opts[:inject] = true
	end

	opt.on_tail('-h', '--help', 'Show this message') do
		$stderr.puts opt
		exit(1)
	end

	begin
		opt.parse!
	rescue OptionParser::InvalidOption, OptionParser::MissingArgument
		puts "Invalid option, try -h for usage"
		exit(1)
	end

	args = ARGV.dup
	if args
		args.each do |x|
			k,v = x.split('=', 2)
			datastore[k] = v.to_s
		end
	end

	if opts.empty?
		puts "no options"
		puts opt
		exit(1)
	end

	if opts[:payload].nil? # if no payload option is selected assume we are reading it from stdin
		opts[:payload] = "stdin"
	end

	return [datastore, opts]
end

def print_status(msg)
	$stderr.puts(Status + msg)
end

def print_error(msg)
	$stderr.puts(Error + msg)
end

def get_encoders(arch, encoder)
	encoders = []

	if (encoder)
		encoders << $framework.encoders.create(encoder)
	else
		$framework.encoders.each_module_ranked(
			'Arch' => arch ? arch.split(',') : nil) { |name, mod|
			encoders << mod.new
		}
	end

	encoders
end

def payload_stdin
	$stdin.binmode
	payload = $stdin.read
	payload
end

def generate_nops(arch, len, nop_mod=nil, opts={})
	opts['BadChars'] ||= ''
	opts['SaveRegisters'] ||= [ 'esp', 'ebp', 'esi', 'edi' ]

	if nop_mod
		nop = $framework.nops.create(nop_mod)
		raw = nop.generate_sled(len, opts)
		return raw if raw
	end

	$framework.nops.each_module_ranked('Arch' => arch) do |name, mod|
		begin
			nop = $framework.nops.create(name)
			raw = nop.generate_sled(len, opts)
			return raw if raw
		rescue
		end
	end
	nil
end

def dump_payloads
	tbl = Rex::Ui::Text::Table.new(
		'Indent'  => 4,
		'Header'  => "Framework Payloads (#{$framework.stats.num_payloads} total)",
		'Columns' =>
			[
				"Name",
				"Description"
			])

	$framework.payloads.each_module { |name, mod|
		tbl << [ name, mod.new.description ]
	}

	"\n" + tbl.to_s + "\n"
end

def dump_encoders(arch = nil)
	tbl = Rex::Ui::Text::Table.new(
		'Indent'  => 4,
		'Header'  => "Framework Encoders" + ((arch) ? " (architectures: #{arch})" : ""),
		'Columns' =>
			[
				"Name",
				"Rank",
				"Description"
			])
	cnt = 0

	$framework.encoders.each_module(
		'Arch' => arch ? arch.split(',') : nil) { |name, mod|
		tbl << [ name, mod.rank_to_s, mod.new.name ]

		cnt += 1
	}

	(cnt > 0) ? "\n" + tbl.to_s + "\n" : "\nNo compatible encoders found.\n\n"
end

def dump_nops
	tbl = Rex::Ui::Text::Table.new(
		'Indent'  => 4,
		'Header'  => "Framework NOPs (#{$framework.stats.num_nops} total)",
		'Columns' =>
			[
				"Name",
				"Description"
			])

	$framework.nops.each_module { |name, mod|
		tbl << [ name, mod.new.description ]
	}

	"\n" + tbl.to_s + "\n"
end

datastore, opts = parse_args

$framework = Msf::Simple::Framework.create(
	:module_types => [Msf::MODULE_PAYLOAD, Msf::MODULE_ENCODER, Msf::MODULE_NOP],
	'DisableDatabase' => true
)

if opts[:list]
	opts[:list].each do |mod|
		case mod
		when /payloads/i
			$stderr.puts dump_payloads
		when /encoders/i
			$stderr.puts dump_encoders(opts[:arch])
		when /nops/i
			$stderr.puts dump_nops
		when /all/i
			$stderr.puts dump_payloads
			$stderr.puts dump_encoders
			$stderr.puts dump_nops
		else
			print_error("Invalid module type")
		end
	end
	exit
end

if opts[:payload]
	if opts[:payload] == 'stdin'
		payload_raw = payload_stdin
		if opts[:encode] and (opts[:arch].nil? or opts[:platform].nil?)
			print_error("Cannot encode stdin payload without specifying the proper architecture and platform")
			opts[:encode] = false
		end
	else
		payload = $framework.payloads.create(opts[:payload])
		if payload.nil?
			print_error("Invalid payload: #{opts[:payload]}")
			exit
		end
	end
end

# set the defaults unless something is already set by the user
if opts[:payload] != 'stdin'
	opts[:arch]     ||= payload.arch[0]
	opts[:platform] ||= payload.platform.platforms
else
	# defaults for stdin payloads users should define them
	print_error("Using X86 architecture and Windows platform for stdin payload to change use -a and --platform")
	opts[:arch] ||= "x86"
	opts[:platform] ||= Msf::Module::PlatformList.transform("Windows")
end
opts[:format]   ||= 'ruby'
opts[:encoder]  ||= nil
opts[:encode]   ||= !(opts[:badchars].nil? or opts[:badchars].empty?)


if opts[:encoder].nil?
	fmt = 'raw'
else
	fmt =  'raw'
	encoders = get_encoders(opts[:arch], opts[:encoder])
end

if payload_raw.nil? or payload_raw.empty?
	payload_raw = payload.generate_simple(
				'Format'        => fmt,
				'Options'       => datastore,
				'Encoder'       => nil)
end

if opts[:template]
	path = File.dirname(opts[:template])
	altexe = File.basename(opts[:template])
end
exeopts = { :inject => opts[:inject], :template_path => path, :template => altexe }

# If we were given addshellcode for a win32 payload,
# create a double-payload; one running in one thread, one running in the other
if opts[:addshellcode] and opts[:platform].include?(Msf::Module::Platform::Windows) and opts[:arch] == 'x86'
	payload_raw = Msf::Util::EXE.win32_rwx_exec_thread(payload_raw,0,'end')
	file = ::File.new(opts[:addshellcode])
	file.binmode
	payload_raw << file.read
	file.close
end

if opts[:encode]
	done = false
	encoders = get_encoders(opts[:arch], opts[:encoder])
	encoders.each do |enc|
		next if not enc
		begin
			break if done
			#enc.datastore.import_options_from_s(datastore, '_|_')
			skip = false
			raw = nil

			if not opts[:iterations]
				opts[:iterations] = 1
			end
			#puts opts[:badchars].inspect

			1.upto(opts[:iterations].to_i) do |iteration|
					begin
						raw = enc.encode(payload_raw.dup, opts[:badchars], nil, opts[:platform])
					rescue Msf::EncodingError
						print_error("#{enc.refname} failed: #{$!.class} : #{$!}")
						skip = true
						break
					end
					if opts[:space] and opts[:space] > 0 and raw.length > opts[:space]
						print_error("#{enc.refname} created buffer that is too big (#{raw.length})\n\n")
						skip = true
						break
					end

					print_status("#{enc.refname} succeeded with size #{raw.length} (iteration=#{iteration})\n")
					payload_raw = raw.dup
					if iteration == opts[:iterations]
						done = true
						break
					end
			end
			next if skip
			exe = Msf::Util::EXE.to_executable_fmt($framework, opts[:arch], opts[:platform], payload_raw, opts[:format], exeopts)
		rescue ::Errno::ENOENT, ::Errno::EINVAL
			print_error("#{enc.refname} failed: #{$!}")
			break

		rescue => e
			print_error("#{enc.refname} failed: #{e.class} #{e}")
			e.backtrace.each { |el|
			$stderr.puts(el.to_s)
			}
		end
	end
end

if opts[:nopsled]
	#puts opts[:arch].class
	nopts = { 'BadChars' => opts[:badchars] }
	nops = generate_nops([opts[:arch]], opts[:nopsled], nil, nopts)
	payload_raw = nops + payload_raw
end

$stdout.binmode
if opts[:format] !~/ruby|rb|perl|pl|c|js|dll|elf/i
	exe = Msf::Util::EXE.to_executable_fmt($framework, opts[:arch], opts[:platform], payload_raw, opts[:format], exeopts)
end

case opts[:format]
when /ruby|rb|perl|pl|c|js_le|raw/i
	$stdout.write Msf::Simple::Buffer.transform(payload_raw, opts[:format])
when /asp/
	asp = Msf::Util::EXE.to_win32pe_asp($framework, payload_raw, exeopts)
	$stdout.puts asp
when /js_be/i
	if Rex::Arch.endian(payload.arch) != ENDIAN_BIG
		print_error("Big endian format selected for a non big endian payload")
		exit
	end
	$stdout.puts Msf::Simple::Buffer.transform(payload_raw, opts[:format])
when /java/i
	if(!exe and payload.platform.platforms.index(Msf::Module::Platform::Java))
		exe = payload.generate_jar.pack
	end

	if exe
		$stdout.write exe
	else
		print_error("Could not generate payload format")
	end
when /elf/i
	if opts[:arch] =~ /x64/
		elf = Msf::Util::EXE.to_linux_x64_elf($framework, payload_raw, exeopts)
	elsif opts[:arch] =~ /x86/
		elf = Msf::Util::EXE.to_linux_x86_elf($framework, payload_raw, exeopts)
	elsif opts[:arch] =~ /arm/
		elf = Msf::Util::EXE.to_linux_armle_elf($framework, payload_raw, exeopts)
	else
		print_error("This format does not support that architecture")
		exit
	end
	$stdout.write elf
when /dll/i
	if opts[:arch] == "x86"
		dll = Msf::Util::EXE.to_win32pe_dll($framework, payload_raw)
	elsif opts[:arch] == "x86_64"
		dll = Msf::Util::EXE.to_win64pe_dll($framework, payload_raw)
	end

	$stdout.write dll
when /exe/i
	$stdout.write exe
when /exe-small/i
when /vba/i
	exe = Msf::Util::EXE.to_win32pe($framework, payload_raw)
	vba = Msf::Util::EXE.to_exe_vba(exe)
	$stdout.puts vba
when /vbs/i
	exe = Msf::Util::EXE.to_win32pe($framework, payload_raw)
	vbs = Msf::Util::EXE.to_exe_vbs(exe)
	$stdout.puts vbs
when /war/i
	if (!exe and payload.platform.platforms.index(Msf::Module::Platform::Java))
		exe = payload.generate_war.pack
	else
		exe = Msf::Util::EXE.to_jsp_war(exe)
	end

	$stdout.write exe
else
	print_error("Unsupported format")
	exit
end