CVE-2023-39674
📋 TL;DR
This CVE describes a buffer overflow vulnerability in D-Link DIR-880 routers via the fgets function. Successful exploitation could allow remote attackers to execute arbitrary code or cause denial of service. All users of affected D-Link DIR-880 router versions are impacted.
💻 Affected Systems
- D-Link DIR-880
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, network infiltration, and persistent backdoor installation.
Likely Case
Router crash causing denial of service, requiring physical reset and temporary network disruption.
If Mitigated
Limited impact if network segmentation isolates the router and regular backups are maintained.
🎯 Exploit Status
The GitHub reference contains technical details that could facilitate exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check D-Link support for latest firmware
Vendor Advisory: https://support.dlink.com/
Restart Required: Yes
Instructions:
1. Visit D-Link support site. 2. Download latest firmware for DIR-880. 3. Log into router admin interface. 4. Navigate to firmware update section. 5. Upload and apply new firmware. 6. Wait for automatic reboot.
🔧 Temporary Workarounds
Disable remote management
allPrevents external exploitation by disabling remote administration features
Network segmentation
allIsolate router management interface to trusted internal network only
🧯 If You Can't Patch
- Replace affected router with supported model
- Implement strict firewall rules blocking all unnecessary traffic to router
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface against affected version A1_FW107WWb08Check Version:
Login to router admin interface and check System Status or Firmware sectionVerify Fix Applied:
Confirm firmware version has been updated to latest available from D-Link📡 Detection & Monitoring
Log Indicators:
- Multiple connection attempts to router management interface
- Unusual traffic patterns to router ports
- Router crash/reboot logs
Network Indicators:
- Unusual payloads sent to router management ports
- Traffic patterns matching buffer overflow exploitation
SIEM Query:
source="router_logs" AND (event="crash" OR event="reboot") OR dest_port=80 AND payload_size>threshold🔗 References
- https://github.com/Davidteeri/Bug-Report/blob/main/D-Link/DIR880%20buffe%20overflow.md
- https://support.dlink.com/
- https://www.dlink.com/en/security-bulletin/
- https://github.com/Davidteeri/Bug-Report/blob/main/D-Link/DIR880%20buffe%20overflow.md
- https://support.dlink.com/
- https://www.dlink.com/en/security-bulletin/
