# imager.rb
#
# Forensic byte-for-byte imaging of remote disks and volumes
#
# R. Wesley McGrew wesley@mcgrewsecurity.com
#    http://mcgrewsecurity.com
# Mississippi State University National Forensics Training Center
#    http://msu-nftc.org

require 'digest/md5'
require 'digest/sha1'

class Metasploit3 < Msf::Post
	
	def initialize(info={})
		super( update_info( info,
			'Name'          => 'Windows Forensic Imaging',
			'Description'   => %q{This module will perform byte-for-byte imaging of remote disks and volumes},
			'License'       => MSF_LICENSE,
			'Version'       => '$Revision: 1 $',
			'Platform'      => ['windows'],
			'SessionTypes'  => ['meterpreter'],
			'Author'        => ['Wesley McGrew <wesley@mcgrewsecurity.com>']
		))
		register_options(
			[
				OptString.new('DEVICE',[true,'Device to image (use enum_drives for possible names)',nil]),
				OptString.new('OUTFILE',[false,'Output filename without extension','image']),
				OptInt.new('SPLIT',[false,'Split image size, in bytes',1610612736]),
				OptInt.new('BLOCKSIZE',[false,'Block size, in bytes (multiples of 512)',1048576]),
				OptInt.new('SKIP',[false,'Skip this many blocks before beginning',0]),
				OptInt.new('COUNT',[false,'Image only this many blocks (0 - read till end)',0])
			], self.class)
	end

	def run
		devname = datastore['DEVICE']
		base_filename = datastore['OUTFILE']
		split = datastore['SPLIT']
		block_size = datastore['BLOCKSIZE']
		skip = datastore['SKIP']
		num_to_read = datastore['COUNT']

		invalid_handle_value = 0xFFFFFFFF
		invalid_set_file_pointer = 0xFFFFFFFF
		fsctl_allow_extended_dasd_io = 0x00090083
		ioctl_disk_get_drive_geometry_ex = 0x000700A0
		
		r = client.railgun.kernel32.CreateFileA(devname, "GENERIC_READ",
			0x3, nil, "OPEN_EXISTING", "FILE_ATTRIBUTE_READONLY", 0)
		handle = r['return']

		if handle == invalid_handle_value
			print_error("Could not open #{devname}")
			raise Rex::Script::Completed
		end
		
		r = client.railgun.kernel32.DeviceIoControl(handle,fsctl_allow_extended_dasd_io,nil,0,0,0,4,nil)
		
		ioctl = client.railgun.kernel32.DeviceIoControl(handle,ioctl_disk_get_drive_geometry_ex,
				"",0,200,200,4,"")
		if ioctl['GetLastError'] == 6:
			ioctl = client.railgun.kernel32.DeviceIoControl(handle,ioctl_disk_get_drive_geometry_ex,
				"",0,200,200,4,"")
		end
		geometry = ioctl['lpOutBuffer']
		
		disk_size = geometry[24,31].unpack('Q')[0]
		
		finished = false
		skip_counter = 0
		if num_to_read != 0
			count = 0
		end
		file_number = 1
		file_data_count = 0
		disk_bytes_count = 0
		fp = ::File.new("%s.%03i" % [base_filename,file_number],"w")
		print_line("Started imaging #{devname} to %s.%03i" % [base_filename,file_number])
		
		md5_hash = Digest::MD5.new
		sha1_hash = Digest::SHA1.new
		
		while finished != true do
			if skip_counter < skip
				print_line("Skipped #{block_size} bytes")
				r = client.railgun.kernel32.SetFilePointer(handle,block_size,0,1)
				if r['return'] == invalid_set_file_pointer
					if r['GetLastError'] != 0
						print_error("Skipped past the end of file?")
						raise Rex::Script::Completed
					end
				end
				skip_counter += 1
				next
			end
		
			if (disk_size - disk_bytes_count) < block_size
				block_size = disk_size - disk_bytes_count
				finished = true
			end
			r = client.railgun.kernel32.ReadFile(handle,block_size,block_size,4,nil)
			disk_bytes_count += block_size
			if disk_bytes_count == disk_size
				finished = true
			end
		
			data = r['lpBuffer'][0,r['lpNumberOfBytesRead']]
		
			if num_to_read != 0
				count += 1
				if count == num_to_read
					finished = true
				end
			end
		
			md5_hash << data
			sha1_hash << data
		
			fp.syswrite(data)
			file_data_count += data.length
			if file_data_count >= split
				fp.close()
				if finished != true
					file_number += 1
					file_data_count = 0
					fp = ::File.new("%s.%03i" % [base_filename,file_number],"w")
					print_line("...continuing with %s.%03i" % [base_filename,file_number])
				end
			end
		end
		fp.close()
		
		print_line("Finished!")
		print_line("MD5  : #{md5_hash.to_s}")
		print_line("SHA1 : #{sha1_hash.to_s}")
		
		client.railgun.kernel32.CloseHandle(handle)
	end
end