CVE-2023-50211
📋 TL;DR
This vulnerability allows attackers on the same network to execute arbitrary code as root on D-Link G416 routers without authentication. The flaw exists in the HTTP service's timestamp processing, where improper length validation leads to a stack-based buffer overflow. Only D-Link G416 router users are affected.
💻 Affected Systems
- D-Link G416 Wireless Router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise with root-level remote code execution, allowing attackers to intercept traffic, modify configurations, install persistent malware, or pivot to other network devices.
Likely Case
Router takeover leading to DNS hijacking, credential theft from network traffic, or deployment of botnet malware.
If Mitigated
Limited impact if router is behind firewall with strict network segmentation and no internal threats exist.
🎯 Exploit Status
ZDI has published technical details but no public exploit code. Attack requires network adjacency but no authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware version 1.10 or later
Vendor Advisory: https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10367
Restart Required: Yes
Instructions:
1. Download firmware version 1.10 or later from D-Link support site. 2. Log into router admin interface. 3. Navigate to Maintenance > Firmware Update. 4. Upload and install the new firmware. 5. Reboot router after installation completes.
🔧 Temporary Workarounds
Disable HTTP Administration
allDisable HTTP access to router administration interface and use HTTPS only
Login to router admin > Management > Access Control > Disable HTTP Access
Network Segmentation
linuxIsolate router management interface to separate VLAN or restrict access to trusted IPs only
iptables -A INPUT -p tcp --dport 80 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
🧯 If You Can't Patch
- Replace affected router with different model that doesn't have this vulnerability
- Place router behind dedicated firewall with strict inbound/outbound rules blocking port 80 access
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under Status > Device Info. If version is below 1.10, device is vulnerable.Check Version:
curl -s http://router-ip/status.cgi | grep firmware_versionVerify Fix Applied:
After updating, verify firmware version shows 1.10 or higher in admin interface. Test HTTP API endpoints for proper error handling.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to API-AUTH endpoints
- Multiple failed buffer overflow attempts in httpd logs
- Unexpected process crashes or restarts of httpd service
Network Indicators:
- Unusual outbound connections from router to unknown IPs
- DNS queries to suspicious domains from router
- Port scanning originating from router
SIEM Query:
source="router-logs" AND (http_method="POST" AND uri="/api-auth" AND content_length>1000) OR process="httpd" AND event="crash"