metasploit-framework/modules/encoders/x86/nonalpha.rb

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require 'msf/core'
require 'rex/encoder/nonalpha'
module Msf
module Encoders
module X86
class NonAlpha < Msf::Encoder::NonAlpha
Rank = LowRanking
def initialize
super(
'Name' => "Non-Alpha Encoder",
'Version' => '$Revision$',
'Description' => %q{
Encodes payloads a non-alpha based bytes. This allows
payloads to bypass both toupper() and tolower() calls,
but will fail isalpha().
},
'Author' => [ 'pusscat'],
'Arch' => ARCH_X86,
'License' => MSF_LICENSE,
'EncoderType' => Msf::Encoder::Type::NonAlpha,
'Decoder' =>
{
'BlockSize' => 1,
})
end
#
# Returns the decoder stub that is adjusted for the size of the buffer
# being encoded.
#
def decoder_stub(state)
state.key = ""
state.decoder_key_size = 0
Rex::Encoder::NonAlpha::gen_decoder()
end
#
# Encodes a one byte block with the current index of the length of the
# payload.
#
def encode_block(state, block)
Rex::Encoder::NonAlpha::encode_byte(block.unpack('C')[0], state.key, state.decoder_key_size)
end
#
# Fix stuff, and add the table :)
#
def encode_end(state)
state.encoded.gsub!(/A/, state.decoder_key_size.chr)
state.encoded.gsub!(/B/, (state.decoder_key_size+5).chr)
state.encoded[0x1E, 0] = state.key
end
end
end end end