CVE-2025-4347
📋 TL;DR
A critical buffer overflow vulnerability in D-Link DIR-600L routers allows remote attackers to execute arbitrary code by manipulating the 'host' parameter in the formWlSiteSurvey function. This affects all DIR-600L routers up to firmware version 2.07B01. The vulnerability is particularly dangerous because these products are no longer supported by the manufacturer.
💻 Affected Systems
- D-Link DIR-600L
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistent backdoor installation, and lateral movement to connected networks.
Likely Case
Router takeover enabling traffic interception, DNS hijacking, credential theft, and botnet recruitment.
If Mitigated
Denial of service or temporary disruption if exploit fails or protections block execution.
🎯 Exploit Status
Public exploit details are available in GitHub repositories. The vulnerability requires no authentication and has straightforward exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: None available
Vendor Advisory: https://www.dlink.com/
Restart Required: No
Instructions:
No official patch exists as the product is end-of-life. The only official recommendation is to replace the hardware with a supported model.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to the router's web interface by disabling remote management features.
Access router web interface > Advanced > Remote Management > Disable
Network Segmentation
allIsolate DIR-600L routers in a separate VLAN with strict firewall rules limiting access.
🧯 If You Can't Patch
- Replace the DIR-600L router with a currently supported model that receives security updates.
- Implement network-level protections: deploy an IPS/IDS with rules to detect and block buffer overflow attempts targeting this vulnerability.
🔍 How to Verify
Check if Vulnerable:
Access router web interface > Tools > System Info > Check firmware version. If version is 2.07B01 or lower, the device is vulnerable.Check Version:
curl -s http://router-ip/SystemInfo.html | grep 'Firmware Version'Verify Fix Applied:
No fix exists to verify. Replacement with supported hardware is the only resolution.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /formWlSiteSurvey with long host parameters
- Multiple failed authentication attempts followed by formWlSiteSurvey access
Network Indicators:
- HTTP traffic to router management interface containing unusually long host parameter values
- Traffic patterns suggesting exploit payload delivery
SIEM Query:
source="router_logs" AND (uri_path="/formWlSiteSurvey" AND (param_length("host") > 100 OR status_code=500))