metasploit-framework/lib/rex/proto/smb/evasions.rb

module Rex
module Proto
module SMB
class Evasions

require 'rex/text'

EVASION_NONE  = 0
EVASION_LOW   = 1
EVASION_HIGH  = 2
EVASION_MAX   = 3

	# Add bogus filler at the end of the SMB packet and before the data
	def self.make_offset_filler(level, max_size = 60000, min_size = 512)	

		if (max_size < 0)
			max_size = 4096
		end
		
		if (min_size < max_size)
			min_size = max_size - 1
		end
		
		case level
			when nil, EVASION_NONE
				return ''
			when EVASION_LOW
				Rex::Text.rand_text(32)
			when EVASION_HIGH
				Rex::Text.rand_text( rand(max_size - min_size) + min_size )
			when EVASION_MAX
				Rex::Text.rand_text( rand(max_size) )
		end
	end
	
	# Obscures a named pipe pathname via leading and trailing slashes
	def self.make_named_pipe_path(level, pipe)
		case level
			when nil, EVASION_NONE
				return '\\' + pipe
			when EVASION_LOW
				return ('\\' * (1024 + rand(512))) + pipe
			when EVASION_HIGH, EVASION_MAX
				return ('\\' * (1024 + rand(512))) + pipe + ('\\' * (1024 + rand(512)))
		end	
	end
	
	# Obscures the TransactNamedPipe \PIPE\ string
	def self.make_trans_named_pipe_name(level)
		case level
			when nil, EVASION_NONE
				return '\\PIPE\\'
			when EVASION_LOW
				return ('\\' * (256 - rand(64)) + 'PIPE\\')
			when EVASION_HIGH
				return Rex::Text.rand_text(512 - rand(128))
			when EVASION_MAX
				return Rex::Text.rand_text(1024 - rand(256))
		end
	end	

end
end
end
end