CVE-2025-4342
📋 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 formEasySetupWizard3 function. This affects 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, creation of persistent backdoors, and lateral movement into connected networks.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept network traffic, or use the device as part of a botnet.
If Mitigated
Limited impact if the device is behind strict network segmentation with no internet exposure, though local network attacks remain possible.
🎯 Exploit Status
Public proof-of-concept code exists in GitHub repositories. The vulnerability requires no authentication and has straightforward exploitation vectors.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: https://www.dlink.com/
Restart Required: No
Instructions:
No official patch is available as D-Link has ended support for DIR-600L routers. The only official recommendation is to replace affected hardware with supported models.
🔧 Temporary Workarounds
Disable Remote Management
allDisable remote administration/management features to prevent internet-based attacks
Access router web interface > Advanced > Remote Management > Disable
Network Segmentation
allIsolate affected routers in separate VLANs with strict firewall rules
🧯 If You Can't Patch
- Replace affected DIR-600L routers with currently supported models
- Implement strict network segmentation and firewall rules to limit router exposure
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface: Login > Tools > System > Firmware InformationCheck Version:
Check via web interface or attempt to access http://router-ip/version.txtVerify Fix Applied:
Verify firmware version is above 2.07B01 (though no fix exists) or confirm router replacement📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /formEasySetupWizard3 with long host parameters
- Multiple failed buffer overflow attempts in web server logs
Network Indicators:
- Unusual traffic patterns to router management interface
- Suspicious payloads in HTTP requests to port 80/8080
SIEM Query:
source="router_logs" AND (uri="/formEasySetupWizard3" AND content_length>1000) OR (http_method="POST" AND user_agent="python-requests" AND uri="/formEasySetupWizard3")