##
# $Id: ssh_version_corrupt.rb 9212 2010-05-03 17:13:09Z jduck $
##

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
##

require 'msf/core'


class Metasploit3 < Msf::Auxiliary

	include Msf::Exploit::Remote::Tcp
	include Msf::Auxiliary::Fuzzer

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'SSH Version Corruption',
			'Description'    => %q{
				This module sends a series of SSH requests with a corrupted version string
			},
			'Author'         => [ 'hdm' ],
			'License'        => MSF_LICENSE,
			'Version'        => '$Revision: 9212 $'
		))
		register_options([
			Opt::RPORT(22),
			OptInt.new('MAXDEPTH', [false, 'Specify a maximum byte depth to test'])
		], self.class)
	end

	def do_ssh_version(pkt,opts={})
		@connected = false
		connect
		@connected = true

		@banner = sock.get_once(-1,opts[:banner_timeout])
		return if not @banner
		sock.put("#{pkt}\r\n")
	end

	def run
		last_str = nil
		last_inp = nil
		last_err = nil

		pkt = make_ssh_version
		cnt = 0

		max = datastore['MAXDEPTH'].to_i
		max = nil if max == 0
		tot = ( max ? [max,pkt.length].min : pkt.length) * 256

		print_status("Fuzzing SSH version string with #{tot} requests")
		fuzz_string_corrupt_byte_reverse(pkt,max) do |str|
			cnt += 1

			if(cnt % 100 == 0)
				print_status("Fuzzing with iteration #{cnt}/#{tot} using #{@last_fuzzer_input}")
			end

			begin
				r = do_ssh_version(str,:banner_timeout => 5)
			rescue ::Interrupt
				print_status("Exiting on interrupt: iteration #{cnt} using #{@last_fuzzer_input}")
				raise $!
			rescue ::Exception => e
				last_err = e
			ensure
				disconnect
			end

			if(not @connected)
				if(last_str)
					print_status("The service may have crashed: iteration:#{cnt-1} method=#{last_inp} string=#{last_str.unpack("H*")[0]} error=#{last_err}")
				else
					print_status("Could not connect to the service: #{last_err}")
				end
				return
			end

			if(not @banner)
				print_status("The service may have crashed (no banner): iteration:#{cnt-1} method=#{last_inp} string=#{last_str.unpack("H*")[0]} ")
				return
			end

			last_str = str
			last_inp = @last_fuzzer_input
		end
	end

	def make_ssh_version
		"SSH-2.0-OpenSSH_5.1p1 Debian-5ubuntu1"
	end
end
