> 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/authentication/offline-password-cracking.md).
# Offline Password Cracking
Offline Password Cracking notes for PortSwigger Web Security Academy labs, including exploitation workflow, payload testing, Burp Suite validation, and remediation context.
### Offline Password Cracking
This lab stores a **pass password in a cookie**. In addition, the comment functionality has a **XSS** vulnerability. / Purpose: to retrieve the **carlos** stay-logged-in cookie, to break its offline password, and then log in as it to delete its account.
**Provided credentials:**
* wiener : peter/ **Victime :** carlos
### 2. How the *stay-logged-in* Cookie Works
When stay logged in is checked, the request sent contains:
```bash
username=wiener&password=peter&stay-logged-in=on
```
The server then returns a **stay-logged-in** cookie encoded in **Base64**:
Decoding →
```bash
d2llbmVyOjUxZGMzMGRkYzQ3M2Q0M2E2MDExZTllYmJhNmNhNzcw
```
* wiener:51dc30ddc473d43a6011e9ebba6ca770
The following diagram is thus used:
### 3. Offline Cracking Attempt via Intruder
In Burp, you can create a payload using:
1. \*\* MD5 password transformation\*\*
* \*\*Prefixed
1. **Base64-encode the whole value**
Then test a dictionary.
→ No conclusive results.
### 4. Exploitation of the XSS in the Comments
The comment field is vulnerable to JavaScript:
```javascript
```
So we can extract cookies via a fetch:
```javascript
```
The request comes on our exploit-server.
### 5. Recovery and Decoding of Carlos' Cookie
Cookie intercepted (Base64):
```bash
c2VjcmV0PXY2UE5LWnJ3czNYSmFNVWtaU09wOWJRbGRCVUVlQnhLOyBzdGF5LWxvZ2dlZC1pbj1ZMkZ5Ykc5ek9qSTJNekl6WXpFMlpEVm1OR1JoWW1abU0ySmlNVE0yWmpJME5qQmhPVFF6
```
Decoding →
* carlos:26323c16d5f4dabff3bb136f2460a943
### 6. Password Cracking
After sending the hash to CrackStation, he returns:
### 7. Finalisation
Connection with:
**carlos : onceuponatime**
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.
Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:
```
GET https://hacking-notes.jord4n.pro/web/authentication/offline-password-cracking.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
