CVE-2021-46441
📋 TL;DR
This vulnerability allows authenticated attackers to execute arbitrary system commands on D-Link DIR-825 G1 routers through the 'webupg' binary due to insufficient parameter validation. Attackers can gain full control of affected devices after obtaining authorization. Only D-Link DIR-825 G1 router users are affected.
💻 Affected Systems
- D-Link DIR-825 G1
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attackers to install persistent malware, intercept network traffic, pivot to internal networks, and use the device as part of a botnet.
Likely Case
Attackers gaining administrative control of the router to modify network settings, intercept credentials, or deploy cryptocurrency miners.
If Mitigated
Limited impact if proper network segmentation and access controls prevent unauthorized access to the router's web interface.
🎯 Exploit Status
Exploitation requires authentication but is straightforward once credentials are obtained
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check D-Link security bulletin for specific patched firmware version
Vendor Advisory: https://www.dlink.com/en/security-bulletin/
Restart Required: Yes
Instructions:
1. Visit D-Link support website
2. Download latest firmware for DIR-825 G1
3. Log into router admin interface
4. Navigate to Firmware Update section
5. Upload and apply new firmware
6. Reboot router
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Change Default Credentials
allUse strong, unique passwords for router admin account
🧯 If You Can't Patch
- Isolate router on separate VLAN with strict access controls
- Implement network monitoring for suspicious command execution patterns
🔍 How to Verify
Check if Vulnerable:
Check firmware version against D-Link security bulletin; test with authenticated command injection if authorizedCheck Version:
Log into router web interface and check System Status or Firmware Version pageVerify Fix Applied:
Verify firmware version matches patched version from vendor advisory📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Multiple failed login attempts followed by successful login
Network Indicators:
- Suspicious outbound connections from router
- Unexpected traffic patterns
SIEM Query:
source="router_logs" AND (cmd="*" OR command="*") AND user="admin"