CVE-2023-44836
📋 TL;DR
A buffer overflow vulnerability in D-Link DIR-823G routers allows attackers to cause Denial of Service (DoS) by sending specially crafted SSID input to the SetWLanRadioSettings function. This affects D-Link DIR-823G A1V1.0.2B05 firmware users. The vulnerability requires network access to exploit.
💻 Affected Systems
- D-Link DIR-823G
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router crash requiring physical reset, potential remote code execution if buffer overflow can be controlled precisely (though not confirmed in this CVE).
Likely Case
Router becomes unresponsive, requiring reboot to restore functionality, disrupting network connectivity for all connected devices.
If Mitigated
No impact if router is patched or network access is restricted to trusted sources only.
🎯 Exploit Status
Public proof-of-concept exists on GitHub. Exploitation appears straightforward via crafted network requests to the vulnerable function.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check D-Link security bulletin for latest patched version
Vendor Advisory: https://www.dlink.com/en/security-bulletin/
Restart Required: Yes
Instructions:
1. Visit D-Link support site. 2. Download latest firmware for DIR-823G A1. 3. Log into router admin interface. 4. Navigate to firmware update section. 5. Upload and install new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable remote administration
allPrevents external attackers from accessing router management interface
Login to router admin → Advanced → Remote Management → Disable
Restrict wireless network access
allUse MAC address filtering to limit which devices can connect to WiFi
Login to router admin → Wireless → Wireless MAC Filter → Enable and add allowed devices
🧯 If You Can't Patch
- Replace affected router with different model that doesn't have this vulnerability
- Place router behind a firewall that blocks access to management interface from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under Maintenance → FirmwareCheck Version:
Login to router web interface and check firmware version, or use nmap to identify device versionVerify Fix Applied:
Confirm firmware version is newer than A1V1.0.2B05 after update📡 Detection & Monitoring
Log Indicators:
- Multiple failed attempts to access SetWLanRadioSettings
- Router crash/reboot logs
- Unusual SSID parameter values in requests
Network Indicators:
- Unusually long SSID values in wireless management traffic
- Requests to router management interface with malformed parameters
SIEM Query:
source="router_logs" AND (message="*SetWLanRadioSettings*" OR message="*crash*" OR message="*reboot*")