CVE-2025-45729
📋 TL;DR
D-Link DIR-823-Pro router firmware version 1.02 has improper permission control that allows unauthorized users to enable and access Telnet services remotely. This affects all users running the vulnerable firmware version, potentially exposing administrative access to attackers.
💻 Affected Systems
- D-Link DIR-823-Pro
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise leading to network infiltration, credential theft, man-in-the-middle attacks, and persistent backdoor installation.
Likely Case
Unauthorized administrative access to router configuration, network traffic monitoring, and potential lateral movement to connected devices.
If Mitigated
Limited impact if Telnet is already disabled and proper network segmentation is in place.
🎯 Exploit Status
Public proof-of-concept available in the referenced advisory. Exploitation requires network access to the router's management interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Check D-Link support portal regularly for firmware updates addressing CVE-2025-45729.
🔧 Temporary Workarounds
Disable Telnet Service
allManually disable Telnet service through router web interface if available
Block Telnet Port
allConfigure firewall rules to block Telnet port 23 inbound and outbound
🧯 If You Can't Patch
- Isolate router on separate VLAN with strict access controls
- Implement network monitoring for Telnet connection attempts on port 23
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface. If version is 1.02, device is vulnerable.Check Version:
Login to router web interface and navigate to System Status or Firmware Information pageVerify Fix Applied:
Attempt to connect to router via Telnet on port 23. Successful connection indicates vulnerability.📡 Detection & Monitoring
Log Indicators:
- Telnet service activation logs
- Unauthorized login attempts on port 23
- Configuration changes without authentication
Network Indicators:
- Unexpected Telnet traffic on port 23
- Telnet connections from unauthorized IP addresses
SIEM Query:
source_port:23 OR destination_port:23 AND (action:denied OR action:allowed) | stats count by src_ip, dest_ip