CVE-2021-46231
📋 TL;DR
This vulnerability in D-Link DI-7200GV2.E1 routers allows attackers to execute arbitrary operating system commands via the url_en parameter in the urlrd_opt.asp function. Attackers can gain complete control of affected devices, potentially compromising entire networks. Only devices running the specific vulnerable firmware version are affected.
💻 Affected Systems
- D-Link DI-7200GV2.E1
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device takeover leading to network compromise, data exfiltration, lateral movement to other systems, and persistent backdoor installation.
Likely Case
Device compromise allowing network traffic interception, credential theft, and use as pivot point for further attacks.
If Mitigated
Limited impact if device is behind firewalls with strict egress filtering and network segmentation.
🎯 Exploit Status
Public proof-of-concept code exists. Exploitation requires web interface access but no authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Later firmware versions (check D-Link advisory)
Vendor Advisory: https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10284
Restart Required: Yes
Instructions:
1. Download latest firmware from D-Link support site. 2. Log into router web interface. 3. Navigate to System Tools > Firmware Upgrade. 4. Upload new firmware file. 5. Wait for automatic reboot.
🔧 Temporary Workarounds
Disable web interface access
linuxBlock external access to router web management interface
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
Network segmentation
allIsolate router management interface to separate VLAN
🧯 If You Can't Patch
- Place device behind firewall with strict inbound rules blocking all access to web interface
- Implement network monitoring for suspicious outbound connections from the router
🔍 How to Verify
Check if Vulnerable:
Check firmware version in web interface under System Status > Firmware VersionCheck Version:
Check via web interface or SSH if enabled: show versionVerify Fix Applied:
Confirm firmware version is newer than v21.04.09E1 after upgrade📡 Detection & Monitoring
Log Indicators:
- Unusual commands in system logs
- Multiple failed login attempts to urlrd_opt.asp
- Unexpected process execution
Network Indicators:
- Outbound connections from router to suspicious IPs
- Unusual traffic patterns from router management interface
SIEM Query:
source="router_logs" AND (urlrd_opt.asp OR url_en parameter)🔗 References
- https://github.com/pjqwudi/my_vuln/blob/main/D-link/vuln_5/5.md
- https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10284
- https://www.dlink.com/en/security-bulletin/
- https://github.com/pjqwudi/my_vuln/blob/main/D-link/vuln_5/5.md
- https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10284
- https://www.dlink.com/en/security-bulletin/
