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When you discover a bug on one subdomain, always test it across other subdomains of the same target. Many vulnerabilities, such as XSS, SQLi, or authentication flaws, may exist across multiple subdomains due to shared configurations or libraries.
You Should Know:
1. Subdomain Enumeration
Use tools like Sublist3r, Amass, or `Findomain` to discover subdomains:
sublist3r -d example.com -o subdomains.txt amass enum -d example.com -o subdomains_amass.txt findomain -t example.com -u subdomains_findomain.txt
2. Automated Vulnerability Scanning
Run `Nuclei` or `Gobuster` to test for common vulnerabilities:
nuclei -l subdomains.txt -t ~/nuclei-templates/ gobuster dir -u https://sub.example.com -w /path/to/wordlist.txt
3. Manual Testing with Burp Suite
- Configure Burp Suite’s scope to include all subdomains (
.example.com). - Use Burp Repeater to manually test endpoints.
4. Check for Misconfigurations
Test for:
- CORS Misconfigurations:
curl -H "Origin: evil.com" -I https://sub.example.com
- DNS Takeover Vulnerabilities:
dig CNAME vulnerable-sub.example.com
5. Exploit Chaining
If you find an XSS on one subdomain, check if it affects others due to shared cookies or authentication tokens.
What Undercode Say
Bug hunting across subdomains is a powerful technique because many organizations overlook security consistency. Always:
– Document findings (use `Dradis` or Obsidian).
– Automate repetitive tasks (Bash + Python).
– Stay stealthy (rotate user-agents, use proxies).
Expected Output:
A structured report listing vulnerable subdomains, proof-of-concept exploits, and remediation steps.
Prediction
As organizations expand their web presence, subdomain vulnerabilities will remain a critical attack surface. Automated tools will improve, but manual testing will still uncover the most severe flaws.
(No URLs extracted as the original post did not contain any.)
References:
Reported By: Yahia Sila – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
