CVE-2023-45576
📋 TL;DR
This CVE describes a critical buffer overflow vulnerability in multiple D-Link router models that allows remote attackers to execute arbitrary code without authentication. Attackers can exploit this by sending specially crafted requests to the upnp_ctrl.asp function's remove_ext_proto/remove_ext_port parameter. Organizations using affected D-Link DI-7003GV2, DI-7100G+V2, DI-7100GV2, DI-7200G+V2, DI-7200GV2, DI-7300G+V2, and DI-7400G+V2 routers are at risk.
💻 Affected Systems
- D-Link DI-7003GV2.D1
- D-Link DI-7100G+V2.D1
- D-Link DI-7100GV2.D1
- D-Link DI-7200G+V2.D1
- D-Link DI-7200GV2.E1
- D-Link DI-7300G+V2.D1
- D-Link DI-7400G+V2.D1
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to full network access, data exfiltration, ransomware deployment, and persistent backdoor installation across the entire network segment.
Likely Case
Remote code execution allowing attackers to pivot to internal networks, intercept traffic, modify device configurations, and establish persistent access for future attacks.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering, though lateral movement risk remains if initial access is achieved.
🎯 Exploit Status
Public proof-of-concept exists in GitHub repositories. The vulnerability requires no authentication and has simple exploitation vectors, making it attractive for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check D-Link official website for firmware updates
2. Download latest firmware for your specific model
3. Access router web interface
4. Navigate to firmware update section
5. Upload and apply new firmware
6. Reboot device after update
🔧 Temporary Workarounds
Disable UPnP Service
allDisable Universal Plug and Play service to block access to vulnerable endpoint
Restrict Web Interface Access
allConfigure firewall rules to restrict access to router web interface from untrusted networks
🧯 If You Can't Patch
- Isolate affected devices in separate network segments with strict firewall rules
- Implement network monitoring and intrusion detection for suspicious traffic to router management interfaces
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface or SSH/Telnet if enabled. Compare against affected version list.Check Version:
Login to router web interface and check System Status or Firmware Information pageVerify Fix Applied:
Verify firmware version has been updated beyond affected versions. Test UPnP functionality if service remains enabled.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to upnp_ctrl.asp
- Multiple failed buffer overflow attempts
- Unexpected device reboots or configuration changes
Network Indicators:
- Unusual outbound connections from router
- Traffic spikes to router management interface
- Suspicious payloads in HTTP requests to router
SIEM Query:
source="router_logs" AND (uri="*upnp_ctrl.asp*" OR message="*buffer overflow*" OR message="*arbitrary code*")