# Kali Linux Course #717: XSser$ Penetration Testing Tool
## Section 1: Introduction to XSser$
XSser$ is a powerful tool for detecting and exploiting Cross-Site Scripting (XSS) vulnerabilities in web applications. This section will guide you through the installation and configuration of XSser$ on Kali Linux, its usage, as well as real-world use cases. By the end of this section, you should have a comprehensive understanding of how to utilize XSser$ for penetration testing.
### 1.1 Installation and Configuration on Kali Linux
#### Prerequisites
Before installing XSser$, ensure you have the following:
– A Kali Linux installation (preferably the latest version).
– Basic understanding of terminal commands.
– Root access or sudo privileges.
#### Installation Steps
1. **Update the Package Repository**
Start by updating your package repository to ensure you have the latest versions of all packages:
sudo apt update
sudo apt upgrade -y
2. **Install XSser$**
XSser$ is available in the Kali Linux repositories. To install it, run the following command:
sudo apt install xsser
3. **Verify Installation**
Once installed, you can verify the installation by checking the version of XSser$:
xsser –version
You should see output indicating the version of XSser$ that is installed.
4. **Configuration**
XSser$ does not require extensive configuration, but it's good to familiarize yourself with its configuration options. You can find the configuration file under `/etc/xsser/xsser.conf`. You can customize options such as default payloads and request methods if needed.
To edit the configuration file, use your preferred text editor:
sudo nano /etc/xsser/xsser.conf
After making any changes, save the file and exit the editor.
### 1.2 Step-by-Step Usage
XSser$ provides a command-line interface, and understanding its parameters is crucial for effective usage. Below, we will cover common commands and options.
#### Basic Command Structure
The basic syntax for running XSser$ is as follows:
"`bash
xsser [options]
"`
#### Common Options
– `-u` or `–url`: Specify the target URL.
– `-p` or `–payload`: Specify a custom payload.
– `-d`: Enable debugging mode for verbose output.
– `-o`: Output results to a file.
– `-t`: Specify a number of threads for concurrent requests.
#### Example Usage
Let’s start with a basic XSS vulnerability scan against a sample URL:
"`bash
xsser -u "http://example.com/vulnerable_page.php?param="
"`
This command will test the specified URL for potential XSS vulnerabilities by injecting default payloads.
### 1.3 Real-World Use Cases
#### Use Case 1: Testing a Login Form
Suppose we have a login form at `http://example.com/login`. To check for XSS vulnerabilities in the username field, we can use XSser$:
"`bash
xsser -u "http://example.com/login?username="
"`
This command will inject XSS payloads into the `username` parameter to check for vulnerabilities.
#### Use Case 2: Testing a Search Functionality
Let’s say there’s a search function available at `http://example.com/search`. We can test this functionality for XSS as follows:
"`bash
xsser -u "http://example.com/search?query="
"`
By doing so, XSser$ will analyze the response from the server and detect if any injected scripts execute.
### 1.4 Technical Explanations
The XSser$ tool operates by sending various payloads to the target URL and analyzing the response. It checks for signs of XSS vulnerabilities, such as:
– Reflection of injected payloads in the response.
– Execution of scripts in the client-side context.
XSS vulnerabilities can be categorized into three types:
1. **Stored XSS**: The malicious script is stored on the server (e.g., in a database) and served to users.
2. **Reflected XSS**: The script is reflected off a web server and executed immediately.
3. **DOM-based XSS**: The vulnerability exists in the client-side code rather than the server-side response.
### 1.5 External Reference Links
For further reading and detailed technical information, refer to the following resources:
– [XSser$ Official Documentation](https://www.kali.org/tools/xsser$)
– [OWASP XSS Prevention Cheat Sheet](https://owasp.org/www-community/OWASP_XSS_Prevention_Cheat_Sheet)
– [Common XSS Attack Payloads](https://owasp.org/www/community/OWASP_XSS_Payloads)
### 1.6 Code Examples for WordPress
If you're working with WordPress, XSser$ can also be used to test plugins and themes for XSS vulnerabilities. Here are some examples of how you might structure your commands.
#### Example 1: Testing a Custom Plugin
Assuming your custom plugin has a vulnerable endpoint at `http://example.com/wp-content/plugins/myplugin/vulnerable.php?input=`
"`bash
xsser -u "http://example.com/wp-content/plugins/myplugin/vulnerable.php?input="
"`
#### Example 2: Testing a Theme Functionality
If there’s a theme feature at `http://example.com/?page_id=123¶meter=`, you can test it as follows:
"`bash
xsser -u "http://example.com/?page_id=123¶meter="
"`
By following these steps and utilizing XSser$, you can effectively identify XSS vulnerabilities in web applications, providing valuable insights for improving web application security.
—
Made by pablo rotem / פבלו רותם