Class: Rex::Proto::DCERPC::Packet

Inherits:
Object
  • Object
show all
Defined in:
lib/rex/proto/dcerpc/packet.rb

Defined Under Namespace

Classes: UnitTest

Constant Summary collapse

UUID = 
Rex::Proto::DCERPC::UUID

Class Method Summary collapse

Class Method Details

.make_alter_context(uuid, vers) ⇒ Object

Create a standard DCERPC ALTER_CONTEXT request packet



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# File 'lib/rex/proto/dcerpc/packet.rb', line 146

def self.make_alter_context(uuid, vers)
	u = Rex::Proto::DCERPC::UUID

	# Process the version strings ("1.0", 1.0, "1", 1)
	bind_vers_maj, bind_vers_min = UUID.vers_to_nums(vers)
	xfer_vers_maj, xfer_vers_min = UUID.vers_to_nums(UUID.xfer_syntax_vers)

	buff =
	[
		5,      # major version 5
		0,      # minor version 0
		14,     # alter context
		3,      # flags
		0x10000000,     # data representation
		72,     # frag length
		0,      # auth length
		0,      # call id
		5840,   # max xmit frag
		5840,   # max recv frag
		0,      # assoc group
		1,      # num ctx items
		0,      # context id
		1,      # num trans items
		UUID.uuid_pack(uuid),   # interface uuid
		bind_vers_maj,       # interface major version
		bind_vers_min,       # interface minor version
		UUID.xfer_syntax_uuid,  # transfer syntax
		xfer_vers_maj,       # syntax major version
		xfer_vers_min,       # syntax minor version
	].pack('CCCCNvvVvvVVvvA16vvA16vv')
end

.make_bind(uuid, vers) ⇒ Object

Create a standard DCERPC BIND request packet



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# File 'lib/rex/proto/dcerpc/packet.rb', line 14

def self.make_bind(uuid, vers)

	# Process the version strings ("1.0", 1.0, "1", 1)
	bind_vers_maj, bind_vers_min = UUID.vers_to_nums(vers)
	xfer_vers_maj, xfer_vers_min = UUID.vers_to_nums(UUID.xfer_syntax_vers)

	# Create the bind request packet
	buff =
	[
		5,      # major version 5
		0,      # minor version 0
		11,     # bind type
		3,      # flags
		0x10000000,  # data representation
		72,     # frag length
		0,      # auth length
		0,      # call id
		5840,   # max xmit frag
		5840,   # max recv frag
		0,      # assoc group
		1,      # num ctx items
		0,      # context id
		1,      # num trans items
		UUID.uuid_pack(uuid),   # interface uuid
		bind_vers_maj,       # interface major version
		bind_vers_min,       # interface minor version
		UUID.xfer_syntax_uuid,  # transfer syntax
		xfer_vers_maj,       # syntax major version
		xfer_vers_min,       # syntax minor version
	].pack('CCCCNvvVvvVVvvA16vvA16vv')

	return buff, 0
end

.make_bind_fake_multi(uuid, vers, bind_head = 0, bind_tail = 0) ⇒ Object

Create an obfuscated DCERPC BIND request packet



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# File 'lib/rex/proto/dcerpc/packet.rb', line 49

def self.make_bind_fake_multi(uuid, vers, bind_head=0, bind_tail=0)

	bind_head = bind_head.to_i
	bind_tail = bind_tail.to_i
	bind_head = rand(6)+10 if bind_head == 0
	bind_tail = rand(4)+1 if bind_head == 0

	u = Rex::Proto::DCERPC::UUID

	# Process the version strings ("1.0", 1.0, "1", 1)
	bind_vers_maj, bind_vers_min = UUID.vers_to_nums(vers)
	xfer_vers_maj, xfer_vers_min = UUID.vers_to_nums(UUID.xfer_syntax_vers)

	bind_total = bind_head + bind_tail + 1
	bind_size  = (bind_total * 44) + 28
	real_ctx, ctx = 0, 0

	# Create the header of the bind request
	data =
	[
		5,      # major version 5
		0,      # minor version 0
		11,     # bind type
		3,      # flags
		0x10000000,  # data representation
		bind_size,   # frag length
		0,      # auth length
		0,      # call id
		5840,   # max xmit frag
		5840,   # max recv frag
		0,      # assoc group
		bind_total,  # num ctx items
	].pack('CCCCNvvVvvVV')

	# Generate the fake UUIDs prior to the real one
	1.upto(bind_head) do ||
		# Generate some random UUID and versions
		rand_uuid = Rex::Text.rand_text(16)
		rand_imaj = rand(6)
		rand_imin = rand(4)

		data +=
		[
			ctx,        # context id
			1,          # num trans items
			rand_uuid,  # interface uuid
			rand_imaj,  # interface major version
			rand_imin,  # interface minor version
			UUID.xfer_syntax_uuid,  # transfer syntax
			xfer_vers_maj,       # syntax major version
			xfer_vers_min,       # syntax minor version
		].pack('vvA16vvA16vv')
		ctx += 1
	end

	# Stuff the real UUID onto the end of the buffer
	real_ctx = ctx;
	data +=
	[
		ctx,      # context id
		1,        # num trans items
		UUID.uuid_pack(uuid),   # interface uuid
		bind_vers_maj,       # interface major version
		bind_vers_min,       # interface minor version
		UUID.xfer_syntax_uuid,  # transfer syntax
		xfer_vers_maj,       # syntax major version
		xfer_vers_min,       # syntax minor version
	].pack('vvA16vvA16vv')
	ctx += 1


	# Generate the fake UUIDs after the real one
	1.upto(bind_tail) do ||
		# Generate some random UUID and versions
		rand_uuid = Rex::Text.rand_text(16)
		rand_imaj = rand(6)
		rand_imin = rand(4)

		data +=
		[
			ctx,        # context id
			1,          # num trans items
			rand_uuid,  # interface uuid
			rand_imaj,  # interface major version
			rand_imin,  # interface minor version
			UUID.xfer_syntax_uuid,  # transfer syntax
			xfer_vers_maj,       # syntax major version
			xfer_vers_min,       # syntax minor version
		].pack('vvA16vvA16vv')
		ctx += 1
	end

	# Return both the bind packet and the real context_id
	return data, real_ctx
end

.make_request(opnum = 0, data = "", size = data.length, ctx = 0, object_id = '') ⇒ Object

Used to create standard DCERPC REQUEST packet(s)



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# File 'lib/rex/proto/dcerpc/packet.rb', line 216

def self.make_request(opnum=0, data="", size=data.length, ctx=0, object_id = '')

	opnum = opnum.to_i
	size  = [4000, size.to_i].min
	ctx   = ctx.to_i

	chunks, frags = [], []
	ptr = 0

	# Break the request into fragments of 'size' bytes
	while ptr < data.length
		chunks.push( data[ ptr, size ] )
		ptr += size
	end

	# Process requests with no stub data
	if chunks.length == 0
		frags.push( make_request_chunk(3, opnum, '', ctx, object_id) )
		return frags
	end

	# Process requests with only one fragment
	if chunks.length == 1
		frags.push( make_request_chunk(3, opnum, chunks[0], ctx, object_id) )
		return frags
	end

	# Create the first fragment of the request
	frags.push( make_request_chunk(1, opnum, chunks.shift, ctx, object_id) )

	# Create all of the middle fragments
	while chunks.length != 1
		frags.push( make_request_chunk(0, opnum, chunks.shift, ctx, object_id) )
	end

	# Create the last fragment of the request
	frags.push( make_request_chunk(2, opnum, chunks.shift, ctx, object_id) )

	return frags
end

.make_request_chunk(flags = 3, opnum = 0, data = "", ctx = 0, object_id = '') ⇒ Object

Used to create a piece of a DCERPC REQUEST packet



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# File 'lib/rex/proto/dcerpc/packet.rb', line 180

def self.make_request_chunk(flags=3, opnum=0, data="", ctx=0, object_id = '')

	flags = flags.to_i
	opnum = opnum.to_i
	ctx   = ctx.to_i

	dlen = data.length
	flen = dlen + 24

	use_object = 0

	object_str = ''

	if object_id.size > 0
		flags |= 0x80
		flen = flen + 16
		object_str = UUID.uuid_pack(object_id)
	end

	buff =
	[
		5,      # major version 5
		0,      # minor version 0
		0,      # request type
		flags,  # flags
		0x10000000,     # data representation
		flen,   # frag length
		0,      # auth length
		0,      # call id
		dlen,   # alloc hint
		ctx,    # context id
		opnum,  # operation number
	].pack('CCCCNvvVVvv') + object_str + data
end