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

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

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 150

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, xfer_syntax_uuid = UUID.xfer_syntax_uuid, xfer_syntax_vers = UUID.xfer_syntax_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, xfer_syntax_uuid=UUID.xfer_syntax_uuid, xfer_syntax_vers=UUID.xfer_syntax_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(xfer_syntax_vers)

  if UUID.is? xfer_syntax_uuid
    xfer_syntax_uuid = UUID.uuid_pack(xfer_syntax_uuid)
  end

  # 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
    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 53

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 220

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 184

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