dreamhack web wargame - cookie

#!/usr/bin/python3

from flask import Flask, request, render_template, make_response, redirect, url_for

app = Flask(__name__)

try:

    FLAG = open('./flag.txt', 'r').read()

except:

    FLAG = '[**FLAG**]'

users = {

    'guest': 'guest',

    'admin': FLAG

}

@app.route('/')

def index():

    username = request.cookies.get('username', None)

    if username:

        return render_template('index.html', text=f'Hello {username}, {"flag is " + FLAG if username == "admin" else "you are not admin"}')

    return render_template('index.html')

@app.route('/login', methods=['GET', 'POST'])

def login():

    if request.method == 'GET':

        return render_template('login.html')

    elif request.method == 'POST':

        username = request.form.get('username')

        password = request.form.get('password')

        try:

            pw = users[username]

        except:

            return '<script>alert("not found user");history.go(-1);</script>'

        if pw == password:

            resp = make_response(redirect(url_for('index')) )

            resp.set_cookie('username', username)

            return resp

        return '<script>alert("wrong password");history.go(-1);</script>'

app.run(host='0.0.0.0', port=8000)

#!/usr/bin/python3
from flask import Flask, request, render_template, make_response, redirect, url_for

app = Flask(__name__)

try:
    FLAG = open('./flag.txt', 'r').read()
except:
    FLAG = '[**FLAG**]'

users = {
    'guest': 'guest',
    'admin': FLAG
}

@app.route('/')
def index():
    username = request.cookies.get('username', None)
    if username:
        return render_template('index.html', text=f'Hello {username}, {"flag is " + FLAG if username == "admin" else "you are not admin"}')
    return render_template('index.html')

@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'GET':
        return render_template('login.html')
    elif request.method == 'POST':
        username = request.form.get('username')
        password = request.form.get('password')
        try:
            pw = users[username]
        except:
            return '<script>alert("not found user");history.go(-1);</script>'
        if pw == password:
            resp = make_response(redirect(url_for('index')) )
            resp.set_cookie('username', username)
            return resp 
        return '<script>alert("wrong password");history.go(-1);</script>'

app.run(host='0.0.0.0', port=8000)

 

 

로그인할 때 쿠키를 setting함. 그리고 cookie의 username 값이 admin이어야 flag를 획득할 수 있음. 

우선 guest로 로그인을 한 다음, 개발자도구에서 cookie의 username을 admin으로 수정해주었다.