# Clickjacking
## What is Clickjacking
Clickjacking is an attack that **tricks** a **user** into **clicking** a webpage **element** which is **invisible** or disguised as another element. This can cause users to unwittingly download malware, visit malicious web pages, provide credentials or sensitive information, transfer money, or purchase products online. \(From [here](https://www.imperva.com/learn/application-security/clickjacking/)\).
### Prepopulate forms trick
Sometimes is possible to **fill the value of fields of a form using GET parameters when loading a page**. An attacker may abuse this behaviours to fill a form with arbitrary data and send the clickjacking payload so the user press the button Submit.
### Populate form with Drag&Drop
If you need the user to **fill a form** but you don't want to directly ask him to write some specific information \(like your email or and specific password that you know\), you can just ask him to **Drag&Drop** something that will write your controlled data like in [**this example**](https://lutfumertceylan.com.tr/posts/clickjacking-acc-takeover-drag-drop/).
### Basic Payload
```markup
Click me
```
### Multistep Payload
```markup
Click me first
Click me next
```
### Drag&Drop + Click payload
```markup
.
1. Click and press delete button
3.Click me
2.DRAG ME TO THE RED BOX
```
### XSS + Clickjacking
If you have identified a **XSS attack that requires a user to click** on some element to **trigger** the XSS and the page is **vulnerable to clickjacking**, you could abuse it to trick the user into clicking the button/link.
Example:
_You found a **self XSS** in some private details of the account \(details that **only you can set and read**\). The page with the **form** to set this details is **vulnerable** to **Clickjacking** and you can **prepopulate** the **form** with GET parameters._
An attacker could prepared a **Clickjacking** attack to that page **prepopulating** the **form** with the **XSS payload** and **tricking** the **user** into **Submit** the form. So, **when the form is submited** and the values are modified, the **user will execute the XSS**.
## How to avoid Clickjacking
### Client side defences
It's possible to execute scripts on the client side that perform some or all of the following behaviours to prevent Clickjacking:
* check and enforce that the current application window is the main or top window,
* make all frames visible,
* prevent clicking on invisible frames,
* intercept and flag potential clickjacking attacks to the user.
#### Bypass
As frame busters are JavaScript then the browser's security settings may prevent their operation or indeed the browser might not even support JavaScript. An effective attacker workaround against frame busters is to use the **HTML5 iframe `sandbox` attribute**. When this is set with the `allow-forms` or `allow-scripts` values and the `allow-top-navigation` value is omitted then the frame buster script can be neutralized as the iframe cannot check whether or not it is the top window:
```markup
```
Both the `allow-forms` and `allow-scripts` values permit the specified actions within the iframe but top-level navigation is disabled. This inhibits frame busting behaviours while allowing functionality within the targeted site.
Depending on the type of Clickjaking attack performed **you may also need to allow**: `allow-same-origin` and `allow-modals` or [even more](https://www.w3schools.com/tags/att_iframe_sandbox.asp). When preparing the attack just check the console of the browser, it may tell you which other behaviours you need to allow.
### X-Frame-Options
The **`X-Frame-Options` HTTP response header** can be used to indicate whether or not a browser should be **allowed** to render a page in a `` or `