hacktricks/pentesting-web/reverse-tab-nabbing.md
Carlos Polop a268747dc2 A
2024-02-09 08:14:36 +01:00

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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
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# Description
In a situation where an **attacker** can **control** the **`href`** argument of an **`<a`** tag with the attribute **`target="_blank" rel="opener"`** that is going to be clicked by a victim, the **attacker** **point** this **link** to a web under his control (a **malicious** **website**). Then, once the **victim clicks** the link and access the attackers website, this **malicious** **website** will be able to **control** the **original** **page** via the javascript object **`window.opener`**.\
If the page doesn't have **`rel="opener"` but contains `target="_blank"` it also doesn't have `rel="noopener"`** it might be also vulnerable.
A regular way to abuse this behaviour would be to **change the location of the original web** via `window.opener.location = https://attacker.com/victim.html` to a web controlled by the attacker that **looks like the original one**, so it can **imitate** the **login** **form** of the original website and ask for credentials to the user.
However, note that as the **attacker now can control the window object of the original website** he can abuse it in other ways to perform **stealthier attacks** (maybe modifying javascript events to ex-filtrate info to a server controlled by him?)
# Overview
## With back link
Link between parent and child pages when prevention attribute is not used:
![https://owasp.org/www-community/assets/images/TABNABBING_OVERVIEW_WITH_LINK.png](https://owasp.org/www-community/assets/images/TABNABBING\_OVERVIEW\_WITH\_LINK.png)
## Without back link
Link between parent and child pages when prevention attribute is used:
![https://owasp.org/www-community/assets/images/TABNABBING_OVERVIEW_WITHOUT_LINK.png](https://owasp.org/www-community/assets/images/TABNABBING\_OVERVIEW\_WITHOUT\_LINK.png)
## Examples <a href="#examples" id="examples"></a>
Create the following pages in a folder and run a web server with `python3 -m http.server`\
Then, **access** `http://127.0.0.1:8000/`vulnerable.html, **click** on the link and note how the **original** **website** **URL** **changes**.
{% code title="vulnerable.html" %}
```markup
<!DOCTYPE html>
<html>
<body>
<h1>Victim Site</h1>
<a href="http://127.0.0.1:8000/malicious.html" target="_blank" rel="opener">Controlled by the attacker</a>
</body>
</html>
```
{% endcode %}
{% code title="malicious.html" %}
```markup
<!DOCTYPE html>
<html>
<body>
<script>
window.opener.location = "http://127.0.0.1:8000/malicious_redir.html";
</script>
</body>
</html>
```
{% endcode %}
{% code title="malicious_redir.html" %}
```markup
<!DOCTYPE html>
<html>
<body>
<h1>New Malicious Site</h1>
</body>
</html>
```
{% endcode %}
## Accessible properties <a href="#accessible-properties" id="accessible-properties"></a>
In the scenario where a **cross-origin** access occurs (access across different domains), the properties of the **window** JavaScript class instance, referred to by the **opener** JavaScript object reference, that can be accessed by a malicious site are limited to the following:
- **`opener.closed`**: This property is accessed to determine if a window has been closed, returning a boolean value.
- **`opener.frames`**: This property provides access to all iframe elements within the current window.
- **`opener.length`**: The number of iframe elements present in the current window is returned by this property.
- **`opener.opener`**: A reference to the window that opened the current window can be obtained through this property.
- **`opener.parent`**: This property returns the parent window of the current window.
- **`opener.self`**: Access to the current window itself is provided by this property.
- **`opener.top`**: This property returns the topmost browser window.
However, in instances where the domains are identical, the malicious site gains access to all properties exposed by the [**window**](https://developer.mozilla.org/en-US/docs/Web/API/Window) JavaScript object reference.
# Prevention
Prevention information are documented into the [HTML5 Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/HTML5\_Security\_Cheat\_Sheet.html#tabnabbing).
## References
* [https://owasp.org/www-community/attacks/Reverse_Tabnabbing](https://owasp.org/www-community/attacks/Reverse_Tabnabbing)
<details>
<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
Other ways to support HackTricks:
* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@carlospolopm**](https://twitter.com/hacktricks_live)**.**
* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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