Exploiting Exposed Source Code via Subdomain Zip File Vulnerability

A security researcher discovered a critical vulnerability where a subdomain (support.example.com) exposed a zip file (support.example.com.zip) containing the entire website source code, including sensitive database and admin credentials. This misconfiguration allowed unauthorized access to critical infrastructure, leading to potential compromise.

You Should Know:

1. How to Identify Such Vulnerabilities

• Subdomain Enumeration: Use tools like Sublist3r, Amass, or `FFUF` to discover subdomains.

  sublist3r -d example.com
  ffuf -w wordlist.txt -u https://FUZZ.example.com -fs 0
  

• Directory Bruteforcing: Check for common backup filenames (backup.zip, www.zip, source.tar.gz).

  ffuf -w /path/to/wordlist.txt -u https://support.example.com/FUZZ -e .zip,.bak,.tar
  

2. Analyzing Exposed Source Code

• Extract and inspect files for credentials, API keys, or misconfigurations:

  unzip support.example.com.zip
  grep -r "password|admin|DB_" extracted_folder/
  

• Check configuration files (config.php, .env, web.config).

3. Mitigation Steps for Developers

• Disable Directory Listings: Ensure web servers do not expose directory contents.

  Options -Indexes  Apache
  autoindex off;  Nginx
  

• Restrict Backup File Access: Use `.htaccess` or server rules to block .zip, .sql, `.bak` downloads.

  <FilesMatch "\.(zip|bak|sql)$">
  Deny from all
  </FilesMatch>
  

• Automated Scanning: Implement CI/CD checks for accidental credential exposure.

4. Reporting & Earning Bounties

• Even if a company lacks a bug bounty program, report responsibly via [email protected].
• Use frameworks like CWE-530 (Exposure of Backup File) to justify severity.

What Undercode Say:

Exposed source code via misconfigured subdomains remains a common yet high-risk flaw. Always:
– Hunt for backups (.zip, .tar, .bak).
– Scan for credentials (grep -Ri "secret\|pass").
– Secure your own apps by disabling unnecessary file listings.

Expected Output:

A detailed report including:

• Vulnerable subdomain (support.example.com).
• Exposed file (support.example.com.zip).
• Extracted credentials (if any).
• Recommended fixes (disable indexing, restrict backups).

References:

Reported By: Shivangmauryaa Bug – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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