metasploit-framework/lib/rex/parser/fs/ntfs.rb

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module Rex
module Parser
###
#
# This class parses the contents of an NTFS partition file.
# Author : Danil Bazin <danil.bazin[at]hsc.fr> @danilbaz
#
###
class NTFS
#
# Initialize the NTFS class with an already open file handler
#
def initialize(file_handler)
@file_handler = file_handler
data = @file_handler.read(4096)
# Boot sector reading
@bytes_per_sector = data[11, 2].unpack("S")[0]
@sector_per_cluster = data[13].unpack("C")[0]
@cluster_per_mft_record = data[64].unpack("c")[0]
if @cluster_per_mft_record < 0
@bytes_per_mft_record = 2**(-@cluster_per_mft_record)
@cluster_per_mft_record = @bytes_per_mft_record.to_f / @bytes_per_sector / @sector_per_cluster
else
@bytes_per_mft_record = @bytes_per_sector * @sector_per_cluster * @cluster_per_mft_record
end
@bytes_per_cluster = @sector_per_cluster * @bytes_per_sector
@mft_logical_cluster_number = data[48, 8].unpack("Q")[0]
@mft_offset = @mft_logical_cluster_number * @sector_per_cluster * @bytes_per_sector
@file_handler.seek(@mft_offset)
@mft = @file_handler.read(@bytes_per_mft_record)
end
#
# Gather the MFT entry corresponding to his number
#
def mft_record_from_mft_num(mft_num)
cluster_from_attribute_non_resident(mft_record_attribute(@mft)[128]["data"], mft_num * @cluster_per_mft_record, @bytes_per_mft_record)
end
#
# Get the size of the file in the $FILENAME (64) attribute
#
def real_size_from_filenameattribute(attribute)
filename_attribute = attribute
filename_attribute[48, 8].unpack("Q")[0]
end
#
# Gather the name of the file from the $FILENAME (64) attribute
#
def filename_from_filenameattribute(attribute)
filename_attribute = attribute
length_of_name = filename_attribute[64].ord
# uft16 *2
d = ::Encoding::Converter.new("UTF-16LE", "UTF-8")
d.convert(filename_attribute[66, (length_of_name * 2)])
end
#
# Get the file from the MFT number
# The size must be gived because the $FILENAME attribute
# in the MFT entry does not contain it
# The file is in $DATA (128) Attribute
#
def file_content_from_mft_num(mft_num, size)
mft_record = mft_record_from_mft_num(mft_num)
attribute_list = mft_record_attribute(mft_record)
if attribute_list[128]["resident"]
return attribute_list[128]["data"]
else
return cluster_from_attribute_non_resident(attribute_list[128]["data"])[0, size]
end
end
#
# parse one index record and return the name, MFT number and size of the file
#
def parse_index(index_entry)
res = {}
filename_size = index_entry[10, 2].unpack("S")[0]
filename_attribute = index_entry[16, filename_size]
# Should be 8 bytes but it doesn't work
# mft_offset = index_entry[0.unpack("Q",:8])[0]
# work with 4 bytes
mft_offset = index_entry[0, 4].unpack("<I")[0]
res[filename_from_filenameattribute(filename_attribute)] = { "mft_offset" => mft_offset, "file_size" => real_size_from_filenameattribute(filename_attribute) }
res
end
#
# parse index_record in $INDEX_ROOT and recursively index_record in
# INDEX_ALLOCATION
#
def parse_index_list(index_record, index_allocation_attribute)
offset_index_entry_list = index_record[0, 4].unpack("<I")[0]
index_size = index_record[offset_index_entry_list + 8, 2].unpack("S")[0]
index_entry = index_record[offset_index_entry_list, index_size]
res = {}
while index_entry[12, 4].unpack("<I")[0] & 2 != 2
res.update(parse_index(index_entry))
# if son
if index_entry[12, 4].unpack("<I")[0] & 1 == 1
# should be 8 bytes length
vcn = index_entry[-8, 4].unpack("I")[0]
res_son = parse_index_list(index_allocation_attribute[vcn * @bytes_per_cluster + 24, index_size * @bytes_per_cluster], index_allocation_attribute)
res.update(res_son)
end
offset_index_entry_list += index_size
index_size = index_record[offset_index_entry_list + 8, 2].unpack("S")[0]
index_entry = index_record [offset_index_entry_list, index_size]
end
# if son on the last
if index_entry[12, 4].unpack("<I")[0] & 1 == 1
# should be 8 bytes length
vcn = index_entry[-8, 4].unpack("I")[0]
res_son = parse_index_list(index_allocation_attribute[vcn * @bytes_per_cluster + 24, index_size * @bytes_per_cluster], index_allocation_attribute)
res.update(res_son)
end
res
end
#
# return the list of files in attribute directory and their MFT number and size
#
def index_list_from_attributes(attributes)
index_root_attribute = attributes[144]
index_record = index_root_attribute[16, index_root_attribute.length - 16]
if attributes.key?(160)
return parse_index_list(index_record, attributes[160])
else
return parse_index_list(index_record, "")
end
end
def cluster_from_attribute_non_resident(attribute, cluster_num = 0, size_max = ((2**31) - 1))
lowvcn = attribute[16, 8].unpack("<Q")[0]
highvcn = attribute[24, 8].unpack("<Q")[0]
offset = attribute[32, 2].unpack("<S")[0]
real_size = attribute[48, 8].unpack("<Q")[0]
attribut = ""
run_list_num = lowvcn
old_offset = 0
while run_list_num <= highvcn
first_runlist_byte = attribute[offset].ord
run_offset_size = first_runlist_byte >> 4
run_length_size = first_runlist_byte & 15
run_length = attribute[offset + 1, run_length_size]
run_length += "\x00" * (8 - run_length_size)
run_length = run_length.unpack("<Q")[0]
offset_run_offset = offset + 1 + run_length_size
run_offset = attribute[offset_run_offset, run_offset_size]
if run_offset[-1].ord & 128 == 128
run_offset += "\xFF".force_encoding("BINARY") * (8 - run_offset_size)
else
run_offset += "\x00" * (8 - run_offset_size)
end
run_offset = run_offset.unpack("<q")[0]
size_wanted = [run_length * @bytes_per_cluster, size_max - attribut.length].min
if cluster_num + (size_wanted / @bytes_per_cluster) >= run_list_num && (cluster_num < run_length + run_list_num)
run_list_offset = (run_offset + old_offset + [cluster_num - run_list_num, 0].max) * @bytes_per_cluster
run_list_offset = run_list_offset.to_i
@file_handler.seek(run_list_offset)
data = ""
while data.length < size_wanted
data += @file_handler.read(size_wanted - data.length)
end
attribut += data
end
offset += run_offset_size + run_length_size + 1
run_list_num += run_length
old_offset = run_offset
end
attribut = attribut[0, real_size]
attribut
end
#
# return the attribute list from the MFT record
# deal with resident and non resident attributes (but not $DATA due to perforemence issue)
#
def mft_record_attribute(mft_record)
attribute_list_offset = mft_record[20, 2].unpack("C")[0]
curs = attribute_list_offset
attribute_identifier = mft_record[curs, 4].unpack("I")[0]
res = {}
while attribute_identifier != 0xFFFFFFFF
# attribute_size=mft_record[curs + 4, 4].unpack("I")[0]
# should be on 4 bytes but doesnt work
attribute_size = mft_record[curs + 4, 2].unpack("S")[0]
#print_debug("attribute_size: #{attribute_size}, attribute_identifier: #{attribute_identifier}")
# resident
if mft_record[curs + 8] == "\x00"
content_size = mft_record[curs + 16, 4].unpack("<I")[0]
content_offset = mft_record[curs + 20, 2].unpack("S")[0]
res[attribute_identifier] = mft_record[curs + content_offset, content_size]
else
# non resident
if attribute_identifier == 128
res[attribute_identifier] = mft_record[curs, attribute_size]
else
res[attribute_identifier] = cluster_from_attribute_non_resident(mft_record[curs, attribute_size])
end
end
if attribute_identifier == 128
res[attribute_identifier] = { "data" => res[attribute_identifier], "resident" => mft_record[curs + 8] == "\x00" }
end
curs += attribute_size
attribute_identifier = mft_record[curs, 4].unpack("I")[0]
end
res
end
#
# return the file path in the NTFS partition
#
def file(path)
repertory = mft_record_from_mft_num(5)
index_entry = {}
for r in path.split("\\")
attributes = mft_record_attribute(repertory)
index = index_list_from_attributes(attributes)
#print_debug("#{index}")
unless index.key?(r)
fail ArgumentError, "File path does not exist", caller
end
index_entry = index[r]
repertory = mft_record_from_mft_num(index_entry["mft_offset"])
end
file_content_from_mft_num(index_entry["mft_offset"], index_entry["file_size"])
end
end
end
end
# f = open(ARGV[0],"r")
# ntfs = NTFS.new(f)
# puts ntfs.file(ARGV[1])
# f.close