CVE-2025-6158
📋 TL;DR
A critical stack-based buffer overflow vulnerability in D-Link DIR-665 routers allows remote attackers to execute arbitrary code by sending specially crafted HTTP POST requests. This affects all DIR-665 routers running firmware version 1.00. The vulnerability is particularly dangerous because these products are no longer supported by the manufacturer.
💻 Affected Systems
- D-Link DIR-665
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistent backdoor installation, network traffic interception, and lateral movement to other devices on the network.
Likely Case
Remote code execution allowing attackers to gain full control of the router, modify DNS settings, intercept network traffic, or use the device as part of a botnet.
If Mitigated
Limited impact if the device is behind a firewall with strict inbound rules and network segmentation prevents lateral movement.
🎯 Exploit Status
Proof-of-concept exploit code is publicly available on GitHub. The vulnerability requires no authentication and can be exploited remotely via HTTP.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: N/A
Restart Required: No
Instructions:
No official patch is available since the product is end-of-life. The only secure solution is to replace the device with a supported model.
🔧 Temporary Workarounds
Network Segmentation and Access Control
linuxIsolate the vulnerable router from critical networks and restrict inbound HTTP access
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
Disable Remote Administration
allTurn off remote management features in the router web interface
🧯 If You Can't Patch
- Immediately replace the DIR-665 router with a supported model that receives security updates
- Place the router behind a firewall that blocks all inbound HTTP/HTTPS traffic from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check the router web interface or console for firmware version 1.00. The device is vulnerable if running this exact version.Check Version:
Check router web interface at http://[router-ip]/ or use telnet/ssh if enabledVerify Fix Applied:
Since no patch exists, verification requires confirming the device has been replaced or isolated from the network.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to router management interface
- Multiple failed login attempts followed by buffer overflow patterns
- Unexpected process crashes or router reboots
Network Indicators:
- HTTP traffic containing unusually long POST parameters
- Traffic patterns suggesting exploitation attempts from external IPs
- Unexpected outbound connections from the router
SIEM Query:
source="router.log" AND (http_method="POST" AND (uri="/" OR uri="/goform/*") AND content_length>1000)